She is in 7th grade now and has been playing violin since kindergarten. She has been playing piano for about 5 years, I suppose. It's not like she wants to quit either piano or violin, she just wants to do clarinet, too. She is an amazingly gifted violinist but while my wife and I think she is lazy with respect to practice (and homework), that is probably par for the course for kids. Hate to be too hard on her. Her mother's brother and a cousin on her mother's side are gifted in the same way. One of them has taught himself about half a dozen instruments, at least. So, with music, while I hate to feel that it's "different", I am much more willing to subsidize clarinet than ski club or the skateboard she recently asked for.

I was a bit lazy with practice myself, sometimes because I didn't have to work very hard to keep up with classmates, sometimes because my piano teacher was quite uninspiring. There were times when my mom had to force me to practice. I was a kid. And practice is rarely as fun as actually playing.

As for whether you treat certain things differently than others, well, you're the parent and it's your money. If you think some things are more valuable then you certainly have the right to subsidize them more than you do other things. You have a finite amount of extras that you can give freely, would you prefer to give her things that are fun or things you think will enrich her future? That's not to say give her no fun, of course... I don't know if that paragraph actually says what I'm trying to say but I'm posting it anyway in case it does.