Katie Did It is correct, it varies. I recently came back from a long trip where I had very few orgasms and didn't really feel like cumming much during that time. But after I got home I was doing two or three per day for a while and it felt great! Then the desire decreased a bit about 4 - 5 per week (so there were a couple days off while the body recovered).
Just listen to your body; it will tell you how many is OK.