This is kind of O.T but I've never really understood this: "Don't wait too late in your rounds fund raise before you apply" When you "do a round" is there som

This is kind of O.T but I've never really understood this: "Don't wait too late in your rounds fund raise before you apply" When you "do a round" is there some sort of legally binding time and funding limit? Or is this just some kind of self imposed thing (like when you're selling vacuum cleaners door to door and say to the customer "Better get in quick! We only have 5 vacuum cleaners left and they're selling fast!").