It is, but it sucks to do it. What I do is not the maths - I already know it’s good for me. I just tell myself, every time:

I’ll just do as much as I can, and when I feel like stopping, I’ll stop.

And then I end up pushing through most of the time. The most important thing is to not pressure yourself to do the same or more every time, but to do your exercises consistently, and frequently. I try to do my sets every other day. In fact, today is one such day. I’m writing this because I’m procrastinating; I’m gonna go do my sets.