You cannot make an omelette without breaking eggs. If you don't make mistakes, you don't make anything. He laughs best who laughs last. God helps them that help themselves. Look before you leap.
Necessity is the mother of invention.
A bird in the hand is worth two in the bush. Don't cut off your nose to spite your face. Take care of the pence and the pounds will take care of themselves. Little strokes fell great oaks. The rich man has his ice in the summer and the poor man gets his in the winter.