I look at it this way, I bought my first bass (1978 P-bass) back in 1981 and still have it. It takes more than just a few years for the instrument to really become a part of you. I got another bass in 1997 (1997 Jazz bass) and I can say it's now become a part of me and my favorite but my P-bass has the history from my teen years as my first new bass and all the wear came from my hands and this bass will always be with me. I can't see owning anymore basses just based on the time factor alone especially as you get older. Many of our bass heroes have stayed loyal to one primary bass even though they can own as many as they want. Many have made a change midway in their career but then are just as loyal to that new instrument as they were to their old one.