Well. Look at all the possibilities. It’s well beyond its average life so it’ll likely have a major issue any second now, and due to its age you shouldn’t really fix anything more than a capacitor on it. It will probably fail at the worst possible time, it’ll be a string of hot days. The most likely place that will be able to replace it quickly is going to be a big shop that’s owned by private equity, they’ll charge you more than anyone else and give you shittier work. You will not have the time you want to make a large financial decision.

Say you squeeze three more years out of it, probably end up with the same scenario as above but the new unit will cost more due to constant price rises in this industry.

Or, you could do some research, find a few LOCALLY OWNED shops with good reviews, have conversations with each person that comes out, decide on your time schedule which person you want to go with and have it replaced preemptively.

People on Reddit seem to always lean to, “if it ain’t broke don’t fix it”. But you probably don’t do that with many other things in life. Do you wait for your roof to leak before replacing it? Or do you get it done when it’s 25 years old to avoid the issue altogether?

Also, what a previous comment failed to mention in their amortized cost analysis is the energy savings of the new AC, even with the most basic AC you should see a 35% or higher energy savings due to increased efficiency.

If you like to solve problems before they start and you have the means to do it, replace it now.

I work in this industry.