Retroactive child support/prior maintenance

I understand that a person seeking retroactive child support/prior maintenance (e.g., back to the separation date) must provide documentation of actual expenditures during that period. Of course, many of us did not know that we ultimately would not be receiving any support and, therefore, did not keep every receipt at first. What kind of documentation and/or how specific would the court be looking for? Even if I don’t have grocery receipts, would proof of mortgage and utilities payments help in recovering some small part? Is there an affidavit of some sort that will need to be filled out?

Receipts, bank statements and past bills can be used to prove actual expenses. Though an affidavit is not required, I would suggest you create a document summarizing all the expenses to simplify the issue for the judge the supporting documents should be used to corroborate your summary.