What to look for
After static content, switch to neutral grey and look for faint ghost shapes that remain visible.
Keep tests short
Avoid long bright static tests. Pixy uses short panels and warns before intense modes.
Do not trust repair promises
Colour cycling can sometimes reduce temporary retention, but permanent burn-in is not something a web page can reliably fix.
Use normal content too
Judge whether retention appears in real use, not only in extreme inspection conditions.