Update on how long to keep house sale records

I had coffee with my tax accountant friend today and according to her I only have to keep the actual tax returns (federal and state) since the houses were sold more than 7 years ago. She added that it is important to keep all supporting documentation for 7 years though. Since we sold the houses 15+ years ago I can whittle the files down.

Please consult your own experts before making your own decisions on this!