How do I decide an appeal against the marker's call?

Question

Accepted Answer

Players appeal by saying "Appeal, please" (World Squash Singles Rule 10). Either player may stop during a rally to appeal a lack of call; the loser of a rally may appeal any call or lack of call. Nothing before the latest serve can be appealed except a broken ball, and an appeal on the last rally of a game must be immediate. If it's unclear which return is being appealed, ask; if there are several appeals, consider each one.

You find	Decision
The marker's call (or no call) was correct	The rally result stands
The marker's call was wrong	Let, unless the call interrupted a winning return by either player, in which case that player wins the rally
The marker didn't call a serve or return that wasn't good	Rally to the other player
You're unsure whether the serve was good	Let
You're unsure whether a return was good	Let, unless the marker's call interrupted the other player's winning return, in which case that player wins the rally

Your decision is final. The marker waits for it and then calls the score. If you disagree with a marker's call or lack of call without any appeal, rule immediately, stopping play if necessary.