If you are just doing riding lessons for fun & to learn a little bit, then once a month is fine. It is hard to put what you learn into practice without riding in-between lessons. I took equitation classes for 2 years in college. The class was weekly but also just went out to a local stable & rented horses for just trail riding about once a month for a change of pace. Didn't ride for years until I retired & decided to take english dressage lessons & show when possible. Bought my horse, then rode almost every day because it took that much practice between lessons to actually get the feel of what I was supposed to do.....but that is a whole different level of riding than just for fun (though it was fun too, but it was also work) Enjoy trail riding with friends who had extra horses that needed riding. When I got my horse finally to my farm, she was sick so much I never rode here here. I love riding so even once a month lessons to enjoy riding is a really good thing to do. Where really depends on your budget & then, if you relate to the person giving the lesson. Maybe go & observe at the stable you don't know a few times & see what it is like before committing to one or the other. Horses are wonderful. I miss my mare so much