For a good, relatively inexpensive flat/tapewound with a good depth and thud to it I think Rotosound Jazz bass 77 take some beating, especially for Precision type basses with a humbucker (the Fender split P Bass pickup is humbucking). The Rotosound nylon tape wrap make a pretty good upright bass kind of sound that works well for some jazz and blues.
As for how often bass strings need changing, somewhere on Carol Kaye's website it says she never changed a set of strings during her decades of peak demand as a session player. Apparently, back when she was playing sessions almost every day, she'd trade a bass in every two years rather than lose work waiting for a refret to be done so the strings never had time to wear out.
Flats/tapes do keep their tone and stability much longer than roundwounds though, so it really depends on the strings themselves.
Roundwound have more treble content and twang and can help fill out a small band and make the percussive slap and pop styles work, but they lose tone over a few months or even less. Stainless roundwounds are very bright. Flats sit more in the bottom of the mix so are less likely to conflict with instruments in the mid frequencies and usually last until the frets start wearing grooves in them.
It might be good idea to get an inexpensive set of each style, try them and see what works best in a band context.
As for makes, I like Rotosound for bass (but not guitar). I suggest avoiding Washburn roundwound, they're very rough and feel like playing on a sharp, coarse wood rasp.