Our pool builder didn't even offer a pool without a timer -- it's just assumed that the homeowner would want to use a timer, and I see why -- it's just one less thing to remember, one less thing to do. Ours runs 8 hrs a day, all months of the year (I'll run the filtration system if we're swimming after 4pm when the timer shuts off the pump). I'm experimenting with how low I can run the variable speed pump and still maintain crystal clear water. Last summer I ran the pump @ 2750rpms. I started this summer running it at 2000 rpms, and just now dropped it to 1800 rpms. I probably won't go lower than 1800 rpms, as that's running the pump at about half-speed.