Statutory Declaration of Common Law - How much evidence is needed?

[Sweet-Tangerine]

My partner's 6 months are up soon, so he's applying for a visitor extension. We need to include that form, and it's asking for supporting evidence. It just doesn't specify how much. We have documents dating back almost 6 years. Do we just need recent proof of living together, etc.? We have a lease and some electric bills together, but not joint bank accounts, life insurance policies, property. How far back should we go? Should we include photos, texts, money transfers, etc.?

We will also be applying for sponsorship soon. So basically I'm asking if we need to provide all of the same evidence, which is dozens and dozens of pages? Or just a simplified version of a few documents?

Thanks.