What's the ideal age for someone to use contacts on a regular basis?!

I think the youngest kid I fit with contacts was about 8, and it worked fairly well. Ideally, I'd prefer age 10 or 11, and I'm much more comfortable if someone else in the house (parents, siblings, whoever) also wear contacts and have experience with it.
I personally feel that daily lenses are much better for young first-time wearers; we don't have to be as concerned about proper cleaning and such when the lenses being replaced after each wear. This isn't always an option, and there's no reason a younger person can't be responsible, but it does tend to be easier.

I'm an optometrist.

I want to say 11 but that's for monthly use. Daily use? 14-15. Hope this helps(: