I've kept mine is privates because she's asked (it's where she got her BHS, and where she's learned drills for tucks and layouts...mainly a fear thing, not something her coach realistically pushed her to have). She didn't start until she was 5, but I took cheer as a very 'Ask me what you want to do, I'll work it in..." She started dance at 2 and did dance at 2 and 3, then asked not to go back, found cheer at 4 and would move into her gym if she could. Over the summer, she practices roughly 8-10 hours a week between team practice, technique classes, and privates.
I'm not a stressed out cheer mom though---I do what she asks for, as long as it's within reason. I've always watched to ensure she's not getting burnt out, isn't overwhelmed...etc. (Child Psychology is my field) The second she shows signs of needing a break, I'll step in.
We move next week back home to Florida, and while we're not 100% sure which side of the state we'll be living on (at this point she could wind up at Brandon, TG Orlando, or Extreme All-Stars), we know we'll be on the East Coast for at least a few weeks. All she talks about is going back to Extreme's 2 hour Open Gym's on Friday nights because she got to go to one on vacation. Why vacation you ask? Because she couldn't stomach going 2 weeks without being in a gym while DH went down to job and house hunt at the end of the summer.
Cheer is her passion, much in the same way Dance was my passion at the same age, so I'm fine with it. But each family has to do what is best for themselves, and I definitely don't judge those who do differently from us.
Her younger sister is into music; with no aspiration to be a cheerleader, she's 4 and I could not imagine her keeping the same schedule as my 6 year old. They're just 2 different little people with 2 different sets of needs.