Thank you for the comment!
You absolutely should be able to perform each task more than once a day! There is a small chance that, when you are working on the conveyor belt, it can break, thus preventing you from doing this job until you fix it, but other than that, you should be able to work at each station multiple times a day. And also, you don't have to do it perfectly each time; in fact, doing it so-so might be more beneficial in terms of time-to-energy ratio. As for the energy, there are ways to replenish it, like a couch or talking to some of the coworkers.
With that said, your comment indicates to me that the balance may be a bit off and we should give the player more time to learn the ropes. Much to consider.