What I heard from my PRO is that an approval is needed is after 5 years, all the documentation should be done again. In the first issue of RP, the period is mentioned, normally 5 years. After the period a fresh process is again required for most of the people. Bank Statements, Rent Agreement etc has to be submitted. If renewal happens after 5 year period based on earlier renewals, ie 6 years approval will be required on the 6th year.