For years, I used to have a Vivitar Series 1 28-90/2.8-3.5 almost permanently mounted to my Canon F-1. It was such a versatile lens, and gave outstanding results. I sold it (and the F-1) when I switched to Nikon, and have never gotten around to replacing it with one in Nikon mount. In my Nikon bag I have mostly primes, and no wide-to-short-tele zooms.
So I usually have a 50mm f/1.4 mounted to my Nikon F2, but also usually the first thing that happens is I replace it with another lens when it comes time to shoot something. That other lens can vary widely depending on the subject matter -- anything from 24mm to 500mm. It just depends. For example, yesterday I spotted a picturesque old train station and caboose in downtown Katy (a satellite city to Houston), which have been turned into a museum. Pulled over and pulled out the F2 with 50mm. One look through the viewfinder told me that my best shots would be done with my 24mm. I took a couple of close-ups with the 50mm anyway, then replaced it with the 24mm, and used that lens for the rest of the shoot.
But if I would have spotted some interesting birds, let's say, I would have reached for my longest lens instead. It just depends.
Michael