If there is a gig, then I tend to pull out the horn I'll use, and give the practice session to it. The rehersal will also have this horn. If any doubt, then I go back to the Strad as a baseline.
Under normal practice and rehersals I mix it up, and give a lot of rotations. Even my Chinese BG gets a play. I enjoy the character and sounds of all the horns, and when I have the horn in the hand, I practice tunes that best fit that character. (Ballads etc with more mellow sounds etc). Classical with the C, and Eb, but mostly the Bb's get the rotatation on a daily basis. Some do sit for a month without being given a chance, but all get a look in at the home practice room.