Position sizing is the single highest-impact decision a trader makes. 0DTE compresses every emotional and mathematical mistake into a few hours. If your size is wrong, no setup or strategy can save you.

This cluster covers the rules we treat as non-negotiable: maximum risk per trade as a percentage of account, stop placement on defined-risk structures, time stops to avoid pin risk into the close, and how to scale down (not up) during a losing streak.

None of this is glamorous. All of it is the difference between a trader who is still trading next year and one who is not.