worth (one's) while
Beneficial and not a waste of one's time. I was reluctant to do research at a different library, but it turned out to be totally worth my while, as they had a ton of books on my topic! Will you drive me to the party tonight? I'll make it worth your while—how about I do your chores for a week?
worth one's while
1. Merit one's time or efforts, as in It's hardly worth your while to count the transactions; it can be done by computer. [Late 1600s]
2. make something worth one's while. Compensate one for one's time or efforts, as in If you take care of our yard while we're away, I'll make it worth your while. [Mid-1800s] Both usages employ while in the sense of "a period of time spent."