My band practices once a week, for about 3 hours. On weekends when we gig, we still try to practice once during the gig.
We're constantly adding / trying new stuff, so there's never any less practice time. Even if we don't have new material to work on, we consistently brush up on our set list. Very often, we take one set per practice and do the entire thing, start to finish. After that, we'll work on new material.
I'm on two bands, both practice once a week. One of them for three hours (seven piece alt-country band) the other for two (all-instrumental trio). When I was younger, my band rehearsed two or three times a week because we had to learn how to play in a band, we were writing and arranging material, and we had nothing else to do. These days, material is brought in by a single writer, we're much more experienced, and we have wives, families and job commitments that preclude that sort of rehearsal schedule.
Each band plays out about twice a month, ironically the one that rehearses more gets only single set gigs, whereas the other always plays two sets, so the totals are five hours a week rehearsing, three hours a week performing.
We practice once/week unless we have a gig and then we usually step it up. Then we have two 3-hour practices. We have three sets so when we play we can go for a few hours.
It is good to get a band to the point where you have a lot of songs and can play gigs without a lot of rehearsal, but I also notice you have to spend time on your own or you can forget songs. We have a gig tomorrow so we rehearsed last night, and out bass player had a bad night, he was forgetting half of the songs and he wasn't realizing he was the one making the mistakes.
We rehearse once or twice per week for three to four hours, and often have a separate meeting once a week. Our gigs, which are two to four per month right now, usually last one to two hours, though we pull the occasional marathon gig (like New Year's Eve)
2x practices at 3-4 hours with about 45 min of breaks,tuning,sound check,etc....
We all do home work as well which really helps with practices focusing on tighter play and less on actual note/chord learning quite as much.
This new band I am starting is tough because I work days and the drummer works nights. So we have only been able to get together for about 2-3 hours on the weekends. It's starting to come together though... I think we finally found a good bass player.