How long can you run something at 100% without it failing?
A lesson I have to constantly relearn for myself. Every couple months my body tells me I've been pushing myself to hard by giving me a crippling headache, fatigue, and nausea.
When in school, I could reliable count on this happening in September, December, March, and May. Since I've been dealing with it so long, I have some semblance of how to deal with the symptoms. Drink more water, eat crackers, then as soon as I get home go to sleep.
I'll wake up the next day feeling fine, and repeat the cycle all over again. The only difference now is that I'm an adult its less consistent to be able to tell when this going to happen. It is less frequent, but the unpredictability is less than ideal.