Out of curiosity would anyone be willing to share any experience with non-paying renters who've vacated the property prematurely?

@Jordyn Ohs Assuming your heloc is re-advanceable and the rate is higher than your mortgage, I would suggest you pay your HELOC down as quickly as possible with any cash flow from the properties.

We're trying to decide whether or not to pay it off or save to buy another property. 

If you have no desire to actively pursue other investments where you make more than a 2.8% return, then by all means pay it off faster.TYFYS and best of luck!

You’re paying $70k in “non-deductible” interest in exchange for less deductible interest. 

So now we cover utilities for both units and the new tenant pays a higher amount too on the back unit to cover all the utilities with a great profit.  

., Purchase Price: $475,000 ($197.9/sq. ft.).Estimated Market Value: $402,000 ($168/sq. ft.).Financing Terms: 2% interest rate, with a 9-year balloon.Unit B Income: $2,049/month (Section 8 tenant through November 2025).Unit A Income Potential: Similar rent or higher; Section 8 cap for the area is $3,234/month.Monthly Loan Payment (P+I): $1,386.Cash Flow Breakdown (if both units are rented at $2,049/month):Gross Rent: $4,098/month.Vacancy (10%): $410/month.Operating Expenses (37.3%): $1,376/month.Net Cash Flow: $943/month.Key QuestionsWould you be comfortable paying an 18% premium for financing at 2%, especially in a market where current mortgage rates are closer to 7%?

Another option is to invest in the market instead of paying down a mortgage.

When you pay off a mortgage you pay the interest for all the years you didn't own the house?!?

Quote from @Leeling Chew: It doesn't matter who pays the bills.