I agree with Boo and the rest - I've been making socks for over 40 years, and have never used a reinforcing thread. Never had one of the heels wear through. Have had several pairs where the toe has developed a hole, though. [note to hubby: Cut Toenails!!!!]
But by all means, do your own thing. Try this for yourself - especially since your son develops holey heels. Make a pair with the reinforcing thread... and another pair without.
Hey, once you start knitting socks, you just can't do it once - right?