I had two basses when I was playing for a living. It was primarily as a backup, but I always made a point to play it at some point during each show. I wish I had kept one of my backup basses - a flawless Guild M-85 semi-hollowbody. I sold that one, which led me to the Embassy, so I guess it was a good deal.
My main bass for the past couple of years has been the Bettie Page fanfret, but I always bring a spare, and usually dedicate a full set to using it (I also rotate the spare). Now that the Embassy is back with me, we'll see how the rotation goes. For the first time ever, I'm actually quite conscious of where I play, and hesitate to bring out certain basses. The Scroll bass stays at home with the exception of one or two clubs that I feel comfortable bringing it to.
My indie band is recording next week, and I plan to have 3 basses with me for that - Epiphone Embassy, Bettie Page fanfret and the Scroll bass.