HELOC: to repay or not to repay?

[Travis Barkel]

Late in 2021 I used a HELOC as the down-payment on a duplex in Michigan. The duplex was turnkey, but has the potential to add a couple bedrooms in the future. Currently it is fully rented so will probably add rooms at the next turnover. My question is: should I be working to repay the HELOC or should I wait? The HELOC has a 10 year interest-only draw period (currently in year 2) after 10 years the loan locks an interest rate and is amortized over 15 years with no further draws. The rate is variable, and is currently at 4.5%. The monthly payment on the $40k that I've borrowed is $125/mo. I have about $10k of cash reserves that I keep for all 3 of my properties for vacancy, Capex, and repairs. The property cash flows even after the HELOC payment so I've been paying $500/mo to knock out the principal but because its a lower rate than I could refinance at today im not likely to do that. Should I be putting that 8k against the HELOC? The HELOC is completely liquid, I can just borrow it back out if I needed a repair or even a vacancy. For some reason the cash in the account feels safer than the HELOC debit card. Should I even be paying the extra principal ever month? Am I thinking about this wrong? Appreciate any and all advice!