I give my son his meds all year. I used to break in the Summer. But the effects of the meds are best if given all year.
I'm sure there are degrees of ADHD.... just like some people are diabetic and need more or less medicine than other diabetics.
Diabetes isn't something most people can control without meds.... so why would we think ADHD is any different? Their brains are different. Why? I don't know, but they are, so why would we think they can "get over it"?
Yes, I believe behavior modification therapy, maturity and diet can all help them manage ADHD, maybe to the point they don't need meds at some point in the future.
I just wonder how your son would do with the meds in Summer... maybe he'd be doing the same or maybe he'd be doing FANTASTIC. It's hard to know how he feels, so why don't you do a trial of on meds for a week and off meds for a week and ask him for his feedback?