Helping hands only last so long

Cameron's training wheels on his bike have recently gotten very worn down, and the rubber part of the wheel on the right side is now continually falling off. So, I--or Colin--are constantly having to take the rubber and slide it back on to the actual 'wheel'. It is beginning to happen more and more frequently, as the training wheels become more worn down each day. That scenario led me to overhear this conversation:

Cameron, to Colin (after Colin had already put the rubber back on his wheel about three times):

"Col, can you please fix my wheel again? I popped a wheelie." (This is what Cameron calls it when the rubber pops off--he has 'popped a wheelie'. I've never corrected him--I'm perfectly content with him believing that he can, in fact, pop a wheelie, without him ever actually trying to pop a wheelie.)

To which, Colin replied:

*Sigh*

"Cam-er-on, I can not fix your popped tires any more. I've been doing it for 60 years. I can only handle so much of this."