Weekly options ("weeklies") expire at the end of each week rather than only monthly. On heavily traded names like SPY, expirations now exist multiple days a week - and zero-days-to-expiration contracts every trading day. They're the short end of the options spectrum.

Why traders use them

Short expirations mean low premiums and high sensitivity to price - a small move in the underlying can produce a large percentage move in the option. That leverage, plus low cost, makes weeklies popular for directional day trades and short-term catalysts. You get maximum bang per dollar.

The decay reality

The flip side is brutal time decay. With days or hours left, an option's extrinsic value evaporates fast - and accelerates into expiration. A weekly that isn't moving your way is losing value every hour, not every week. There's no time to be wrong and wait it out.

Weeklies pay you fast when you're right and punish you fast when you're not. Time is not on your side.

Using them with discipline

Weeklies reward precision - a clear read, a defined level, and a mechanical exit - and destroy accounts that hold and hope. The tight time frame means position sizing and hard exits matter more, not less. They're a scalpel, not a hammer, and they punish the undisciplined without mercy.