Reinforcing sock heels/toes

[GrumpyGramma]

I thought I'd ask before I start another pair....

How do you reinforce toes or heels of socks? I think there is more than one way to do it and I'd like to check them out. (One way I saw, as I recall, has you weave a reinforcing yarn throught the knitted stitches, I know that heel flaps can be slip stitched.) Do you use the same yarn you're knitting with or something else? I've decided I love handmade socks and want to get the most mileage possible out of them.

One other question. Knit Picks has cotton/acrylic sock yarn. Will the acrylic do the same thing as nylon? I think lots of commercially made socks have acrylic and no nylon.