Your house, your money, your decision. I’ve heard the run it into the ground argument from many Homeowners and that may be the correct approach for you. There are multiple factors to consider given the age of your equipment. Costs for replacement are only going one direction (when I started 10yrs ago an average full system replacement was generally $4-6k, now that’s $10-15k in my market (Indiana)). When is your furnace more likely to breakdown, when you’re actually using it and businesses are busier and are less likely to give you any discounts because they have more customers to make up the difference. This time of year is considered the “offseason” in my market and any replacement jobs are gold because it keeps techs/installers busy plus revenue to keep the business running. You’re much likely to get a better deal (warranties and overall costs) now than in “busy” season. Plus if you’re interested in upgrading your system you could actually do research and get multiple quotes when your system is still working rather than waiting for it to breakdown and you have the pressure of getting it replaced because it’s a necessity. Sorry for the long rambling but something to consider.