How to locate them
Look for several visible turns, repeated closes, gaps and areas of volume. Starts on weekly and goes down to daily. Use a noise-friendly fringe, not a false precision line.
Function change
A broken resistance can act as support if old sellers disappear and new buyers defend. Requires acceptance about the area; an isolated wick may be a false rupture.
Example
Zone 48–50 stopped three advances. Weekly close at 52 and retracement that respects 50 with decreasing volume provide more evidence than touching 50 intraday.
Confirm
Observe close, volume, subsequent structure and overall market. The more tests, the more visible the level, but each test also consumes pending orders and can weaken it.
Use it in a plan
Define input, override, and target before acting. The distance to invalidation determines risk; Don't place a stop exactly where normal noise frequently arrives.