How does Hamlet respond to Polonius's pompous assertion that he "will use them according to their desert"?
After the first player fearfully recalls in epic style the story of the slang of King Priam and of Queen Hecuba awful witness to it, Hamlet asks Polonius to look after the players' living quarters.
HAMLET: Good my lord, will you see the players well bestowed? Do you hear, let them be well used ...
POLONIUS: My lord, I will use them according to their desert.
HAMLET: God's bodkin, man, much better. Use every man after his desert, and who shall 'scape whipping? Use them after your own honor and dignity. The less they deserve, the more merit is in your bounty.
Hamlet is moved by and respects the players. Moreover, he has special need of their services. It is through them that he plans to "catch the conscience of the King." Polonius says that he will use the players as they are deserved (desert) to be used. Hamlet responds that Polonius should go out of his way to treat them far better (for if people were to be treated as they deserved, few would escape whipping).