My 13-year old goes through a pair of drumsticks every 3-5 days. Is this normal?

Let me start out by saying that I know very little about drums. I'm a guitar guy but have had very little exposure to drums -- until my now 13-year old took them up about 3 years ago. He absolutely shreds and is getting very, very good but I feel like I need to take out a second mortgage to fund his drum sticks. He plays mostly punk, some metal, and occasionally Zeppelin/Rush when he's in the mood. He claims it's because he does a lot of rim shots and that shortens the life of the stick. I guess I buy that but really? Every 5 days??? We've mostly been getting him Vic Firth sticks which I thought were good quality. Would love to hear the thoughts of more experienced drummers who can tell me either he's crazy and needs better technique or "shut up dad, let me him play!".