Pgbp query

Query : 

If a business entity sells some goods in year 2001 and after 3 years, the goods are returned  as they were defected. 

How should the same be recorded after 3 years ,i.e, in year 2004, in the books of accounts in the following two conditions,

1 ) The defects are regular in nature

2) The defects are not regular and sales returns are not there.