I go out to my shed at least three times a day to feed, add hay etc but I don't spend a long time out there. If they are out in the runs then I tend to pop out frequently to say "hello"! And every other day I clean them out so I spend an hour or so out there, but really its not that much altogether.
I agree with Alison - its not ideal to have an outdoor single bun, and especially not at this time of year. And my rabbits are also much more interested in each other than me . . unless I am bringing food, of course!