A cat has nine lives.
A friend in need is a friend indeed.
A light purse makes a heavy heart.
A man is known by the company he keeps.
A new broom sweeps clean.
A nod is as good as a wink.
A penny saved is a penny earned [gained].
A sound mind in a sound body.
A thing worth doing is worth doing well.
A watched pot never boils.
Absence makes the heart grow fonder.
Accidents will happen.