Used stamps exchanges.

In total there are 100 stamps, 11 of them are damaged. So I can give only 3.

I would give him a 5 instead of a 3 because he sends 89 useful stamps that are in good condition. Many traders send you 100 stamps in good condition but they include 30 or more common older definitive that are useless for most collectors. Would you give a 5 to those collectors ?