Record keeping: what to keep, for how long, when to toss

[Maria Teo]

I'm looking to downsize filing cabinets filled with paper records for my real estate business. (I'm a landlord if that matters.) What documents are necessary to always keep no matter what, what needs to be kept and for how long? Are hard copies necessary, are scanned documents sufficient?

Here is a short list with guesses for length of time to keep. 

1. Taxes - keep at least  7-10 years hard copy (or indefinitely if electronic)
2. Insurance policies - keep current and 1-2 year's past policies
3. Bank statements?
   
4. Legal documentation for tenant/landlord disputes - until tenant leaves?
5. Monthly rental statements?
6. Capital improvement records?
   
   

Anything else I'm overlooking? A lot of my older records don't have electronic copies. I'm loathed to scan everything, but maybe it is worth the pain just to have those records?

Appreciate this communities input.