How many times do you change a tampon a day?

It depends on her flow and what absorbency she is using.

I have hyper-menorrhagia - I would leak through an ultra absorbency tampon, overnight pad, and my clothing within 15 minutes on a heavy day. For most women withmenorrhagia tampons aren't enough to deal with heavy flow, menstrual cups are a better option as they hold more flow, don't leak like tampons, and unlike tampons cups can be worn overnight with no need to alternate with pads.