Hah,
Yea man, I'll chime in on this. I notice we have about the same amount of posts, and the same number of machines. I'd bet that you and I both fall into the "gaining our sea-legs" level of collecting.
My first 3 cabs were a Main Event converted to an MK3 (the "grail" game I wanted), a horribly beaten up and painted black Millipede (converted into Bad Dudes), and a highly sun faded Operation Wolf.
I was 19, I let them sit in storage for two years, paying $80 bucks a month. In the end, I tossed them in the dump after pulling the MK3 board.
So many regrets.
I thought the Main Event cab was the same as the TMNT/Simpsons, and that I would be able to convert it to a dedicated game...wrong. Cab was different, and art was not available at the time, even if it wasn't.
Millipede, at the time Phoenix Arcade had not ran the front art, and Archer McLean (Yes the awesome one) was slowly tackling the side art for his personal cab. I was in somewhat monthly contact with him for a year or so, but he was in no rush. He was doing an awesome job, but it was going to cost a pretty penny coming from the UK.
At some point, I realized that it would be best if all the art came from the same place. Phoenix Arcade had no interest in doing the sides if Archer was already messing with it, and Archer's cab had a great front with no issues. To this day, no one sells the sides, and Archer got out of the whole art business. I of course found out that Millipede art isn't in high demand, as most folks will Multi-pede a Centipede cabinet if they care about the game. Sadly I prefer the Millipede cab's art, but the cab seems less common overall.
With the cost of storage, and the lack of art, I tossed this cab (still regret it) without stripping the parts that many around here could have benefited from.
Operation Wolf, yea, was never going to find replacement art. Still think it does not exist. Again, I should have stripped the parts for someone with a better cab.
So, yes, I have my many regrets.
However, in my mid/late 20's I figured out what I just read someone on the forums call "Phase 2", where you stop buying games to have games, and start buying games you care about.
I found my "Grail" Dedicated MK3 cab, in Tuscon for $80 bucks, a 12 pack of Bud, and a bag of In-N-Out burgers.
A buddy of mine at work who is a little older than me knew I was into collecting and hit me up one day. Said he had a couple of cabs he got off an old buddy who ran an arcade back when he was right out of high school. Was cool with selling them to me for $250. I grabbed a nice Missile Command Cabaret (my mom's favorite) and a little game called Dragon's Lair. Awesome. I swore to him to never sell the DL, not that difficult of a request.
After a while I wanted the full size MC, and someone posted a cab on CL for $100. It wasn't working. I figured I could swap guts from the cabaret to remedy that. Got it home, found out it was a loose cable on the power supply. whole cab works. Picked up Takeman's CP repro...sweet. Still need to order the side art.
Traded cabaret to Jawhn for a Pac-Man cocktail table "project" I'm working on atm.
Point is, hobbies like this are kind of like poker. You have to lose some hands to learn how to play. I'll never buy a cab again that I haven't already sourced artwork for. I ALWAYS verify if the machine is original or a conversion of something else before I buy. Most importantly, I aim for games I care about, and have skipped over many great deals because of it.
Ultimately if you're in it for the long haul, try to look at the mistakes as the cost of learning, and don't make the same one twice.