Evidence required for PR Application

I am an Irish / British Dual National living and working in the UK. My Peruvian wife lives with me here and holds an EEA Family Permit.

My wife has applied for a 5 year residence card and we are currently waiting for that to be processed. The question I have is what documentation / evidence will be required when my wife applies for Permanent Residence in 5 years time. Will we need a wealth of evidence proving that we have been living together for 5 years?

Thanks in advance,