How do you decide what kind of work to schedule when you’re already mentally drained?

Source: Dev.to

Background

I’ve noticed I’m bad at matching my energy level to the work I plan. I’ll block out time for deep work, but sometimes I only realize halfway through that I’m too mentally fried to do it properly.

Questions for the Community

• Do you actively plan your day around how you feel or your stress level?
• When a day goes “off,” what usually breaks the plan or your ability to follow it?
• Have you ever tried time‑blocking or similar planning methods? If so, what didn’t work for you?

Goal

I’m exploring a small personal tool in this space and trying to understand the real pain point. This isn’t a sales pitch—just looking for honest feedback.

Thank you all in advance for your replies.