Today’s expression is “to put all your eggs in one basket”
It means to concentrate all your resources in one thing or place.
It is used in a negative way, because when all your success depends on only one thing, it is very easy to lose everything.
ex1. You would be better if you invested your capital into several companies instead of just one, put all your eggs in one basket.
ex2. You should better pick up some new skills, don’t put all your eggs in one basket.