When installing NVRaM affects features of the game it's probably best to avoid. Locate the batteries inside the coin door for easier inspections if you are worried about leakage.

This is true in the sense that the RTC runs when the power is on but it does not run when the power is not on. The TZ clock displays whatever the RTC returns.

This is NOT true. Theatre of Magic does not have what most people think of as "midnight madness". That's a feature of Dwight Sullivan software. The RTC has nothing to do with "midnight madness" on Theatre of Magic.

How long do you leave your games on?

I switch my TZ on when I'm going to play it, and turn it off afterwards. There have been a few occasions when I've been playing with friends that I've turned it on and left it in attract mode while we've played on the other pins, but that's an exception to the norm.

It is a pretty funky feature, but it takes a good couple of minutes (maybe more?) to kick in, and if you just turn your machine on to play it then maybe you won't even notice it?

That said - I don't have NVRAM, lithium batteries on a remote battery pack are not that big a deal to change once a year.

I would rather sacrifice midnight madness to avoid alkaline damage.

Def nvram. Actual midnight midnight madness will almost never occur anyways, and may be more confusing than anything. Protect that mpu!

Like others have said - Midnight Madness on TOM isn't time-based, it's a mode.
For TZ, having the clock running while the game is off is a necessity for me - I DO turn my gameroom on in its entirety when playing other games, so the clock displays the time quite often.

On TOP of that, IMHO you should be checking those batteries whenever you clean and wax your game - this should be a LOT more than 'once yearly' - unless you play your games VERY infrequently.

I have NVRam in a few of the pins. The couple that doesn't have the NVRAM and I installed Lith batteries.

Just about a year ago I had some spare alkaline batteries set aside for flashlights. New, good name brand that had a shelf date ages from now. Leaked in the sealed package. Whatever you do, don't install alkaline.

On a side note, I have a desoldering gun - sure makes pulling a chip out a lot easier.

Didn't someone make a RTC for pins?

TZ no, TOM why not.

Nvram in most of my games or a remote battery pack mounted the whole way down inside the cab by the coin door with lithium batteries.