question about which odds

[tinhat]

If I know odds to make my hand for street to street (flop to turn, turn to river), should I also know the odds with two cards to come? Why (rather, when is that used)?

And, besides about 35% to make a flush on a four-to-the-flush flop, IIRC 10% to make a set with pp and a couple others, are there some others like this I should be sure to know? Know all in the back of hepfap? Any besides that?

Mike