Buy a project machine. Decide what big components you are going to replace (cab/playfield/etc...) and work it over time.
I don’t have a ton of disposable income ... so I’ve been slowly getting what I need for my Indy (since 2011)... and I’m finally putting it together.
You learn so much by just tearing it down it’s hard to explain. I thought I had it all covered but as I started to really dig in there was what felt like 2x more things I needed. Definitely death by a thousand cuts type of experience.
My next one will be an Addams. Can’t wait.