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."