Do you have fun playing it? That is getting the most out of a pin.

All you really need to do is make sure you're not hurting it with rusty or chipped balls. Clean it once in a while as suggested above, and if something gets lose, fix it, it will just get worse.

At some point you will do a teardown, and yes, the first one is overwhelming. So many parts the fit together. And then they get easier. Take LOTS of pictures from every angle, and then take more. Just hover around the game with a camera, and point to things that look complex in the pictures. Take even more pictures as you take things apart. You will expose stuff that wasn't seen in the first set. As you take things off, hold it in your hand and snap another.

It sounds like overkill, but they will help you put it all back together. After a couple like that, it becomes much easier. You will start to understand how games get put together. And the first one you put back together is a thrill.

You are the steward of the game while you own it. Try to make it better for the next owner, or at least no worse. Then just have fun.