I voted once a day for fruit, as they get a little treat of something each- be it a small piece of banana, apple, a grape, or sometimes a bit of dried pineapple. The dried pineapple is rarer though.
They get veg twice a day. What we do is split their 1/4 cup of pellets into 2 servings. So every morning a half cup (1/8 cup per bunny) is poured into the bowls (2 bowls between 4 bunnies), and then we top with veggies until the bowl is overflowing. Same in the evening. So each bunny gets around 1/4 cup Oxbow BBT pellets and a bowl of veggies per day.
I couldn't not give them veggies everyday- they live for them! At about 7pm if the haven't been fed, they start jumping around and have recently started nudging the bowls to let us know it's dinner time lol
They all do the dinner dance- on tip toes, dancing around, trying to knock the bowl out of Steve's hands! They eat the pellets, but aren't overly fussed about them and sometimes leave some behind, and they always eat lots of hay.
The veg we feed is romaine, sometimes red gem/red leaf lettuce, rocket, spring greens, kale, celery incl leaves, sometimes green pepper, coriander (cilantro), parsley, basil and carrot tops. Carrot in small amounts and occasionally. Probably more veg that I can't think of right now!