Yes, component buying should be in bulk. Main reason is many parts are used multiple times in a machine such as driver transistors and 1N4007 diodes.

Diodes such as the 1N4007 are used so much in just one machine. My friends all buy those in 1000 quantity because it drops the price to just a penny each (or less sometimes).

100% agree with Ken. Buying in bulk is the way to go.

Yep, usually if I need to use one, chances are that I'll need to use another one at some point later.

I always order multiples of common parts & components. It saves time to have most of what I need on-hand, and it saves on shipping costs to bundle a bunch of things together, rather than ordering one at a time.

However, I also do a lot of repairs to begin with, so if you don't do a whole lot of repair work, keeping a large stock of parts might not be all that useful. For components, maybe just keep some spare transistors and diodes.

Yeah, I buy more than I need. Even when it comes to boards.

It's getting to the point where it's probably 50/50 that an old 90s game I find in someone's house where it's been for 10 years or more has battery damage all over the switch matrix. Rottendog boards are $175 - so I just buy at least two of them in a shot. Same with ultimate MPUs. Save a little on shipping, and these will hold their value in the unlikely event I never use them.

It really depends. If you are one or two pin guy - and many of us are - seems pointless to stock up. If you go through dozens of games a year like some of us, might as well buy 100 leg levelers at a time.

That's what my buddy Welby does. Because we go through so many machines, he gets about 200 leg levelers at a time and probably about 500 leg bolts too.

For components, we typically order these quantities:

100 TIP 102 transistors

1000 1N4007 diodes

1000 1N4148 diodes

100 ceramic disc capacitors, .047 uf @ 100 volts (for Bally switches)

20 snap mount electrolytic capacitors, 15000 uf @ 25 volts (for Williams WPC power driver boards)

20 bridge rectifiers, 35 amps 400 volts

You get the idea. The above covers most of what we encounter when we pick up a new (to us) machine of unknown condition.

Yep buy it in bulk. It’s really cheap then you have the parts you need for a while.

If you need 1 buy 3. If you need 2 buy 10. If you need 10 buy 100. If it's cheap enough buy even more anyway because why not

AH-HA! Rare but for once I disagree with Ken!
Don't replace snap mount caps with more snap mount caps. Snap mount caps can too easily damage the board's plated through holes - especially when being replaced for the N'th time.
Use regular leaded radial caps with the same lead pitch of 10mm. A good choice is a Nichicon UVR1E153MRD.

Something else to consider:

Buying just qty1 of the part you need...
What if the new part is bad too?
What if you burn out the new part because another part was bad too?

Here's what I do for parts I don't already have a stockpile of:

If 1 costs $1.00, but 10 cost $2.00, I order 10 and charge the client $2.00 for the single part.

The client will happily pay $1.00 more than he'd normally pay because he didn't have to do any research or 2nd guessing on part compatibility.