"I think it was Harry Walpole who remarked, "In this life one should try everything once except incest and country dancing.

Try everything once. Except incest and folk dancing.’ Sir Thomas Beecham

You've got to try everything once, except those things you don't like, or that involve a lot of effort and getting up early.

I'll try anything once, twice if I like it, three times to make sure.

There's always one more way to do things and that's your way, and you have a right to try it at least once.

There are three things you do only once in your life: born, die and voting on PT!

Nothing twice.
Never eat the same food twice.
Never go to the same place twice.
Never hear the same thing twice.
Everything only once.