Depends. Could be every day, could be once a month. Depends on how much you play them. Some games seem to always have some issues and others very few.

I guess there really is no good answer.

There is no good answer other than 'it depends'. I have had new games that have given me lots of problems and old games that have been on location for a year with a lot of play needing nothing but cleaning.

You can figure out how to repair or maintain them easily enough though so don't worry too much about not being able to DIY. You can and will learn and it is not as hard as you think!

Unfortunately i seem to be fixing my new stern pins more than my 90s pins . Any used pin i get i do redo it so thats probably part of the reason ,but i also believe the newer stuff just isnt made as well....
Again just my opinion

Afm holds up well in most cases . Addams can be tricky but can be very reliable if redone from the get go. Met pro seems to hold up pretty well overall and Aerosmith hasn't been released so no one really knows about it yet....

Take your time and do everything right the first time, and in a home setting, you'll certainly minimize your issues.
There's plenty of good information here, on Vid's guides, or pay for pinball ninja to educate yourself.
Get a proper set of tools, take pictures, double check your work, tighten your hardware.

I'm slowly growing out of Noob phase but I got started with no experience. I knew I could make my way around wires and basic repair stuff. I've found the troubleshooting and reading repair guides and tips and help here part of the fun. Just today I replaced resistors on a flasher board and got the last two flashers on my Pinbot working to make the machine fully functional. Very satisfying. Two years ago I had never even soldered before. Just anticipate that something will break and you'll figure it out and fix it.

If you have any mechanical ability at all, this is the truth. Im no expert by any means but ive learned how to work on them and maintain them pretty good. There are things that could happen though to where I would have to rely on my friends expertise for sure. The best thing about it is though,
I actually enjoy working on them and maintaining them. I have 6 machines, 4 old and 2 new and they have been very reliable for the most part. If you have zero mechanical ability id probably find another hobby, but if you have a little mechanical abilty or alot id say go for it.

Most of the fixes I've had to made are either soldering a broken wire or changing a switch, both of which will require soldering skills. The rest have just been adjustments (mostly), reseating connectors etc. I've had both NIB and older 90's pins and there seems to be no difference in terms of maintenance frequency, the newest Sterns seem to have all sorts of issues due to cheaper components but that's just based on what I've read on pinside

I knew nothing of soldering when I started, so I ordered a couple practice kits from Amazon. I'm still not a pro, but I can get by and I'm not afraid to do that (thanks to the practice). Get good equipment though, if you have a sucky solder pump and a bad soldering iron it'll make even easy jobs difficult.

Also, you'll need some tools. There was a thread on that, but I can't find it.

Don't be afraid of the maintenance jobs, they don't happen that often and it's a great feeling when you successfully troubleshoot something (with help from pinside, if needed) and get it fixed. It's definitely a high!

Everyone above has posted very valid answers For me, a lot of the EM's, if cleaned sufficiently will almost NEVER breakdown. Early 80's pins are more seseptable to having kinda weird issues that can be pretty nerve racking to fix (cold solder joints, people doing really bad board work that you have to fix ) The 80's is a great era of pins but after 35 years, some stuff will normally go wrong. 90's pins usually work great! I've had Bride of Pinbot for one year and I've never had issues! Only an easy flipper rebuild! She works like a dime. I actually kind of wish things would go wrong with the pins because I love fixing them

Learn to work on machines or don't get into the hobby. Had people over last night. 6 people playing on and off for 4 hours across 5 machines and you go into expecting something to break. Was pleasantly surprised to not have to do repairs today. I have 8 machines and was ecstatic to have 0 electrical issues left to work on. First time in months that everything is fully working short of being taken apart for cleaning.

Your only other option is to have deep pockets and pay for all your repairs. That is only an option if you have a tech in your area and not every place does.

I started a couple years ago with zero mechanical ability. I now become ok at fixing problems, but the process has been very time consuming. So many things to learn. I enjoy the process and even like doing repairs, although my main objective is to play, play, play. Online you can find all sort of information, thats great. But then it takes lots of time and patience to put that into practice. I only have '90 machine, and they often have issues. Well, not too often, but something every few weeks is still a lot in my opinion. It means that owning pinball machines imply being able to solve the most usual problems (which are 95% of them all). If not, you will constantly need to call a technician, and that is going to cost a lot. If you only want to play and dont want to learn a lot for maintenance, its not going to last long.

Same here. I'm slowly learning after a few years. I used to be real intimidated about repairs but now it's no big deal. It helps to have more than one pin so you can still play something when one pin is broke. I've met some other guys in the hobby that can help me with the harder stuff like board repair. Most fixes are pretty straightforward and things are not that complicated as it may seem. Some games like my Congo needed a lot of things sorted out up front but then solid for a long time. My first pin Getaway is the oldest but has been rock solid. Only real issue was an opto went bad. My Stern games have been very reliable but have needed tweaks and small fixes like any pin.

Important thing is to turn off power before poking around or even changing a bulb. Learn how the test menus work and get a manual for the game. These are very helpful in figuring out problems. Test menus allow you to test each switch, bulb, and coil independently. Once you identify what switch or part is not working, it becomes a lot easier to figure out the exact problem or better post a question on pinside. I rather be playing than fixing pins but it is rewarding when you fix a problem youtself. Easiest thing to get started with is shopping a pin. Take ramps off playfield, clean everything, wax, replace all rubbers, replace any broken parts, and put in leds.

Part of the adventure is learning. Being able to maintain and troubleshoot your own collection is a gratifying and necessary part of owning a collection. The best part is that you have a wonderful community of folks here to help you.

Marc

A lot of people enjoy repairing/maintaining games. You will learn grasshopper. I couldn't solder until I got my 1st machine. Got to watch a tech repair some games in house and it was a good learning experience. Don't be afraid.

For me, starting from zero, watching online videos has been extremely helpful. Often there is nothing too complicated, but just reading things you never saw in reality keeps it still somehow mysterious. I feel much more confident after watching videos: you see really where and how to put your hands on stuff, and you feel you can do it. For me too the feeling of managing to fx problems is awesome, and after that I feel even more in love with the machine. Anyway, as I said, be ready to battle, because sometimes things can take long times to solve and it can be frustrating.

Having the manual for whatever you work on is important. It's a great help for identification and part numbers. Next, a camera to photograph whatever you're taking apart. It takes all the guesswork out of how parts go back together. You can't take too many pics if your new to pinball repair.
As far as troubleshooting goes, most repairs are common sense. Your right flipper broken ? Lift the play field and look at the coil. Half the time you'll see a broken wire connection. Re-solder. Problem solved. Same flipper won't return ? You'll probably find a hanging spring. Most repairs are that simple to figure out. Good luck !

I agree with all of this particularly that you can't take too many pictures! I have gotten more confident so don't take as many now and found myself putting a STTNG back together recently with what seemed to be an extra plastic and not enough pictures. Fortunately google photo search saved me!

Home use, slim to none

You'll learn a lot as you go, and I recommend asking other collectors in the area if there's someone who does service calls. Its incredibly satisfying to tinker on a problem until you get it fixed, but it can also be really frustrating to hack away at a problem that never seems to resolve. If you know a talented repair person, you can tackle the straightforward stuff and call in for backup as necessary.

Also, I agree with other advice about various machines performing quite differently. For instance, I've had 2 different Addams Family pins- one was a tank, and the other a complete mess. Both eventually developed nagging issues with the Thing hand mechanism, and that area is particularly frustrating to work on since it's so enveloped and tight.

But don't be discouraged- start small, give the game a good once-over when you get it (and feel comfortable) and have fun =)

oh yes, takin pictures! now that I know much better I always do. So much easier to re-assemble. In the beginning I didnt do it, I was always thinking: no need for pics, it's obvious!.. and then taking lots of time to remember the "obvious"..!

A couple of tips that worked for me.

Buy from a local collector who takes very good care of his or her games. I bought Stargate and The Getaway as my first 2 games from a local collector who truly cares for his games and did not have anything break years later. With my help my newbie Neighbor bought a Starship Troppers from him and nothing wrong a year and a half later. Lucky yes, but this was not all luck. Be cool with them and keep in touch and they will help you also I bet.

Make friends with locals who enjoy doing repairs. On rare occasions a friend will stop by to help me with a repair, but mostly add mods. I pay them back by helping them find deals like $6200 STLE's, helping them move games into their houses, giving them my old DMD's free when I upgrade to color, etc and being a fun dude!

+1 for buying games in very good conditions to begin with, especially from a trusted, honest operator. Pay some more but do not start with many problems since the beginning. Saving some money with machines in bad shape is worthed for people who know how to fix machines, but for a newbie is totally not worthed imho.