I have a rub I really like for chuckies, but I don't use it for brisket. I have a rub I like for PB, but I don't use it on ribs. I have a chicken rub I like, but I don't use it on turkey.
I like to try new and different rubs, but I always have my standbys to fall back on...kinda like "comfort" rubs, I guess.
There are endless combinations of rubs and smoke and methods. Why limit yourself to one when the next you try could be your new favorite?
Then again, if you really, really like your current rub and don't want to deviate from it, that's OK too. Its *your* que!