Should you be on call for your job at all times? 

I’m gonna go out on a limb and say, unless you’re a doctor, then no. Even if you are a doctor, you’re not on call all the time. There are times when you’re on call, and there are times when you are off. But certainly for entry-level jobs and customer service roles, you shouldn’t be expected to drop everything just to help out. Sure, it might be nice to cover your coworkers’ shifts sometimes, because it makes you extra money, and you might as well if you’re free. But there are lots of times when that doesn’t quite work out for your schedule. And you should never feel bad about that. It’s the management’s fault if they can’t find anybody to cover the slack. Some jobs have a way of making you feel like everything is your fault. They expect way too much of you, especially in comparison to how much they compensate you.