During tough times, it is important to tighten one's belt and cut unnecessary expenses.

She is tightening her belt to save money.

During the recession, many families had to tighten their belts and cut back on expenses.

He always has windmills in his head.

She picked her battles wisely.

She carefully picks her battles to avoid unnecessary conflicts.

She is picking her battles wisely.

I always eat my dinners at home.

He decided to make his exit before the party got too crowded.

She is having a normal one at the party.