What do you mean by 'looks after'?
btw, first page of search results for 'lazy writer plan cache data cache'
http://msdn.microsoft.com/en-us/library/ms181055%28v=sql.90%29.aspx
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability