I did at first because DD was a baby when she started - swimming (mandatory IMO) at a few months old, gymnastics too, and ballet at 3. Now at 6 she is a fantastic swimmer and loves her lessons, ditto gymnastics, but last year she decided to quit ballet in favour of girl guides. I was a little resistant, and she still misses the recitals, but overall I think it was a great call by her. Ballet was too repetitive and she just didn't need all that practice, and her GG den is awesome.
She has a big wishlist of more activities she wants to do - maybe a different type of dance, tap or hip hop, we looked at an art class but it didn't gel, sometimes she wants to learn a language, sometimes she wants to do netball or soccer, but her big wish is horseriding lessons, which we're going to let her start next year.
Generally we have a rule that we both have to agree, whether it's after-school activities, or what clothes she's wearing smile Not sure how long that rule will last!