I know that my boys (5 and 9) still love the characters and wouldn't get overloaded by them alone. However, I know from experience that character breakfasts tend to take up a good amount of time which we later felt would have been better spent touring the parks and riding rides while the crowds were at their lowest levels. You can avoid that by going before park opening, but we didn't want to have to get up even earlier than we did to make it by park opening. We usually stay at the parks until closing, so we like to let the boys sleep as long as possible. Also, the days we did the character breakfasts, we tended to skip lunch because we were still full and later had character dinners. We were on the dining plan, so we had tons of CS left over. We now try and only do one TS a day or do breakfasts on our departure day when we won't be having dinner at WDW.