It depends on the man really. If he has normal healthy sperm and count, it shouldn't matter too much. If he doesn't it will deplete his count making it harder. I have read some studies that say that doing it every day may deplete sperm count some but it increases the chances that more good healthy sperm are the only one getting thru. In other words, his count may go down but only the bad ones decrease and there are still plenty of good swimmers available. There is alot of research online that might be helpful. Good luck!
Yes, every day can deplete the sperm count. Every other day or even every third day is plenty.