A swarm in May is worth a load of hay; a swarm in June is worth a silver spoon; but a swarm in July is not worth a fly.
One swallow does not make a summer Link to proverb.
All that glitters is not gold.
Bigger they are, the harder they fall - The.
Practice makes perfect.
He who fights and runs away, may live to fight another day.
Don't mix business with pleasure.