This question addresses where time comes from.
However, when I first watched the movie, the first thing I wondered was:
When you pay for your food or for public transport, your time obviously goes into the machine or the other person's personal time. However, when you live that time out, where does it go?
The movie is obviously an allegory of "Time is money". But unlike that movie, in real life, money doesn't disappear (unless you destroy bills and coins, or your bank has a severe glitch in their databases, but that's another story).
If that time were to simply disappear, doesn't it mean the entire world would eventually run out of time? No matter how much time you have, it won't last forever.