what does "touch and go"mean?

Touch and go is commonly used in daily life--i wouldn't say "always" used, it's likely only to be used where it is appropriate.

Touch and go means that the outcome of a situation is uncertain. It is most often used to refer to an event in the past, the outcome of which was uncertain until the very end--usually when the desired outcome has been acheived, but not without worry and uncertainty.

"We worked very hard to finish the report in time for the conference. It was touch and go, but we managed to pull it off, and made our boss look good when she presented the report.