The math: at typical 0.30 delta short put and 5-point wide structure, you collect roughly $1 of credit on a $5-wide spread. Risk is $4, reward is $1, probability of profit is roughly 70%. Expected value works out positive when IV rank is above ~40 — the higher the IV at entry, the better the math. This is the workhorse strategy for premium sellers who want defined risk.
Setup: 30–45 DTE, sell the 0.20–0.30 delta put, buy the next strike or two below for protection. Take profit at 50% of max gain. Stop loss at 200% of credit received (i.e., a $1.00 credit becomes a $2.00 loss before you cut). Avoid running into expiration week — gamma exposure spikes and a single move through the short strike can turn a winning position into max loss in hours.