Implied volatility is the market's bid on how much a stock will move. When you sell a cash-secured put or covered call, IV is literally what you're being paid for — so selling options without checking it is like quoting a job without seeing the site.
What IV rank adds that raw IV doesn't
A 40% implied volatility means nothing in isolation: it's sleepy for one stock and panicked for another. IV rank fixes the context problem — it scores today's IV from 0 to 100 against that same stock's range over the past year. IV rank 75 means the options are richer than they've been 75% of the time. Now the number is comparable across every ticker you trade.
Sell premium when it's expensive, not when you're bored
The premium seller's edge concentrates in high-IV-rank moments: earnings hangovers, sector scares, market-wide dips. Selling a put at IV rank 70 pays you dramatically more per unit of strike risk than the identical trade at IV rank 15. Many disciplined wheel traders simply won't open trades below a rank threshold — 30, 40, 50 depending on appetite — and that one rule does more for returns than any indicator stack.
The trap on the other side
Extremely high IV is a smell, not a gift. A 100% IV rank usually means real news — pending FDA decisions, fraud headlines, binary events. The premium is huge because the risk is huge. The skill is separating recoverable fear (market dragged the stock down) from structural fear (the business changed). If you can't name why IV is elevated, you're not selling insurance, you're selling lottery tickets to people with better information.
Make it measurable
Log the IV rank on every trade you open, then compare outcomes by bucket after a few months. Most traders discover their sub-30 trades barely beat T-bills while their 50-plus trades carry the whole account. Once you can see that in your own numbers, the discipline stops requiring willpower.