My Sweet Pea is a lop rabbit, and when I adopted her... I was so in love and caught up in the moment that I forgot about their being prone to ear issues. She had a bit of a wax build up when she went for her first check-up after my adopting her, but the vet didn't see it as an issue. A little later down the road, my dog kept licking at her ears whenever I had her out, so when she went for a six month check-up (because of a slight, very mild abnormality with her teeth, the vet wanted her in for a bi-annual check up to monitor it).. I mentioned the dog licking at the base of her ears.. Turned out she had a possible ear mite problem. So we started with some drops and a topical treatment.
I was told to keep the drops on hand once the mite situation was cleared up, and the wax in her ears was also a bit of a concern... I was advised to give her the drops at least once a month to control the wax problem.
Again, Sweet Pea is a lop-- and ear issues are fairly common with them. Because of their downward facing ears, they sometimes need a little assistance. With my other two, ears are never a concern. They can groom themselves just fine and their ears get plenty of air into them. Even with my first two buns, which I had for 6 and 7 years, I never had a single issue with their ears.
If you notice head shaking or anything funky with your rabbit's ears, it'd still be best to bring them to a rabbit savvy vet to have it checked out to figure out what the best course of action is. I don't do anything with my rabbits unless I'm advised to by my vet.