It was about nothing, but I'll have to be careful for a while.

Be careful with him for a while, if you can.

"I wanted him to be careful for the good of others."

So maybe they had to be careful for a while.

You have to be careful here- just for your own personal conduct.

"I want you to be very careful for a while."

I want you to be careful for a few days.

But anyway, we need to be rather careful for a while.

I was going to be careful for a long time.

I want you all to be careful for the rest of the night,' Mike said.