How to check a homeowner’s rental history?

[CJ C.]

Hi All - Just got an application from my leasing agent on a house.  This family has a small (think 800 sq ft) paid off house in the same city and is looking to rent my SFM which is 1400 sq ft. They’ve lived in their current house for almost 2 decades - so no real rental history although no evictions either.  They have enough income (>3x) and it is steady although credit history isn’t great (550) - vast majority is due to medical collections for which they get disability.  Any thoughts on how to check “rental payment history”?  They meet the 3x income to rent but I know BiggerPockets rental guides usually want to see that plus good rental payment history and good credit. Also is medical collections something you would overlook / weight lightly?