Pacing is the most important thing I've learned in 7 years of ME. Not the concept — everyone tells you the concept. The actual practice of it. The heart rate monitoring approach (staying under 60% of max HR) is the only thing that's helped me avoid crashes consistently. Garmin watch, set an alert. When it vibrates, I stop. Full stop. It took 6 months before I could do it consistently but my baseline is genuinely better.