By this I mean that you should know several ways to solve each pair, because solving that pair with alg #1 will make the following pair a bad case, but if you solve it with alg #2 then it'll give you a 3 mover.

Something like that.

Or if you have two pairs, knowing which one to do first so you don't end up with a sucky case for the other one.

Basically knowing how every algorithm affects the cube.