Househacking accounting help

[Adam Widder]

Hi all, we house hack a triplex currently. So we've had expenses for repairs, maintenance and improvements. As I do my accounting for these expenses to keep track of them, how do you divide the receipts? Currently I seperate by house expenses, my unit expenses, and other unit expenses.
Is there any reason to track what I spend on my unit for tax purposes?

Should I save receipts? If so, how long?

Thank you!