Constantly! I eventually learned that I'll get weary of any particular tone after awhile, no matter how great it is, and look for greener grass (or fresh meat, pick your analogy). Note that this was a painful lesson to learn: so many instances of "why the hell did I sell that bass??"
I used to be a "one main bass with backup or two" guy, but that changed. I now own 9 basses in a variety of pickup configurations and rotate them regularly: P-style, reverse-P style, MM-style, "soap" style, etc. This year I'm finally going to add a J-style bass to my collection, and that'll probably be it... mainly because I'm running out of storage space for my gear, but even if not, I wouldn't want a larger collection... I like to play 'em all regularly, and of course that's gotten more difficult as I've added basses.
Anyway: my suggestion is to stow your J-bass, don't touch it for awhile (weeks, months, whatever). I predict that you'll get the itch again.