It takes sperm 90 days to grow!!! so every day is fine for a healthy man.
Now if you are doing it more then every 4 hours is when you may run into blank issues (because it takes four hours-about-to get all the semen/sperm back to the right location for another "delivery") He can still deliver babybatter sooner then that but to get a full load (his normal ejaculation amount) you will need 4 hours in between. If you doing more then every four hours you could dehydrate the poor boy

j/k!