My approach to guitar buying is largely utilitarian and based on filling a function rather than just having them to have them. I have three acoustics, all the same model. Guitar 1 is the guitar I learned to play on and got when I was 5-6 years old. It's very important to me and I rarely travel with it. Guitar number 2 is same model and I use it for traveling. Guitar 3 is also same model and I use it for a stage backup or when I have acoustic jams at the house.
I have a strat-style guitar for rock playing, a tele as a stage backup to that, a semi-hollowbody for jazz and blues, an SG-type guitar with humbuckers for heavier songs. Finally, I have an electric traveler that I use to keep guitar withdrawals away on long vacations and long work trips (of which there are many).
And that's it. I also have a lap steel but I consider it to be a piece of home decor.
My WTB guitar list is also small. I want a high-end acoustic. All the acoustics I've ever owned have been in the sub-$300 range. I want a really nice taylor or Tak or Guild acoustic. And I want an electric acoustic nylon string guitar because I have 0 nylon string guitars.