Using levels for stop placement and planning

The most useful job for support and resistance is not predicting where the price will go. It is helping you plan: where you would get in, where you would admit you are wrong, and where you might take profit.

If you buy near support because you think the floor will hold, then a clear break below that floor means your idea was wrong. That gives you a logical place for a stop-loss, an order that closes your position automatically at a set price to limit the loss.