be careful

Of course, there are plenty of good charities out there that are worthy of your generosity, but be careful.

She knew many travellers decided to skip the town and said there were signs in the hostel warning to be careful about drinks.

And you really want to be careful what you wish for,” Sahm said.

He urged them to be careful not to double count and to ensure they write everything down.

I mean, in a sense, be careful what you wish for.