Most I've heard of have manual settings you can use, such as open at 6:00 a.m., close at 8:00 p.m. Those have to be adjusted occasionally though, and especially at Daylight Savings times.
There's a few threads about automatic doors both generally and/or by brand if you search the brand you're considering.
Here's a thread with a bunch of replies on it.
Our automatic doors are my hubby and I. We opted not to get one, although sure would be handy in inclement weather not to have...