I settled on 3 watches in a rotation that I continually wear. I've had as many as 4-5 but I always end-up combining the bottom 2 to trade-up to a new "third" watch. My approach is to spend as much as I can possibly afford (given my personal circumstances at time of purchase) to fill one of 3 categories:
1. Grail/Dress
2. Daily Wearer
3. Beater/Sport
The three that currently fill the bill are as follows:
Grail/Dress - Richard Lange
Daily Wearer - G.O. Senator Navigator Panorama Date (Cal. 100)
Beater/Sport - UTS 1000m v2 GMT
I'm pretty happy with my current 3 watches. But I'm always looking for the "next big thing" to substitute-in and that's what makes it fun. Right now, my "covet" list might include, among others, the Patek Phillipe 5127, G.O. Senator Chronometer, Rolex Submariner (ceramic bezel), G.O. Sport Evolution Panorama Date (I previously owned one...), G.O. Senator Rattrapante, Laurent Ferrier (my ultimate grail....I will never afford this, of course....) and Blancpain Le Brassus (and others that look like it...). I doubt I'll ever be in a position to own more than 1-2 of these but it's fun to dream....
Cheeers
DB Darien