Weekly options decay faster per day than monthlies. That fact is true, easily verified, and the basis of a great deal of advice to sell weeklies for superior returns.

The advice is incomplete in three specific ways, and each of them removes a chunk of the advantage.

The claim, verified

Decay follows roughly the square root of time remaining, so shorter contracts genuinely lose extrinsic value faster per day.

Forty percent against sixteen. On these numbers weeklies win decisively, and if the numbers were complete the argument would be over.

Cost one: friction, multiplied

Selling weeklies means roughly 52 positions a year instead of 12. Every one crosses a bid-ask spread on entry and again on exit, and pays commission both ways.

A $5 round-trip cost against a $105 weekly credit is 4.8%. The same $5 against a $266 45-day credit is 1.9%. Same friction, less than half the drag — and it applies 52 times a year instead of 8.

Cost two: gamma

The one that matters most and never appears in the comparison table.

A 7-day at-the-money option is permanently in the high-gamma zone. Its delta swings violently on small moves, and you are holding that condition continuously rather than visiting it briefly at the end of a longer cycle.

Selling monthlies and closing at 21 days means you spend most of your time in the calm part of the curve and deliberately exit before the twitchy part. Selling weeklies means the twitchy part is the entire trade, every week, all year.

Cost three: attention and error

Fifty-two decisions a year rather than twelve. Fifty-two chances to mis-key a strike, miss an earnings date, or make a rushed choice on a Friday afternoon.

This is not a trivial consideration. Most retail options losses come from execution and judgement errors rather than from mispriced positions, and quadrupling the decision count quadruples the exposure to them.

Where each fits

Monthlies (30-45 days) are the default for good reasons: enough premium to absorb friction, entry outside the high-gamma zone, and few enough decisions to make each one carefully. This is what the rest of the course assumes.

Weeklies earn their place in specific cases: managing around a known event, writing a short-dated call against shares you intend to sell soon, or a highly liquid underlying where friction is genuinely negligible.

Zero-day is a different activity entirely — see 0DTE mechanics.

What can go wrong

Comparing gross annualised figures. They exclude the friction that hits weeklies four times harder.

Ignoring gamma. The higher decay is payment for it, not a bonus.

Underestimating the workload. 52 decisions a year is a job, not a strategy.

Weeklies on illiquid names. The friction alone can exceed the premium advantage.