Heat pump/AC replacement?

I have three and my rig was built in late 03. Two of them get used a fair amount as we are half timers. I bought a spare old style heat pump as a new one will not work with my Tstat without an adapter kit. No I would not replace.

They can go either way, forever or short lived. Our 2005 models lasted 2 years while the replacement 2007 models split, with the rear one failing in less than 7 years and the front, which gets the most use still going strong. Follow TenOC's advice and not worry until the time comes. Also, if you have Dometics, they are completely different now from what you have. We finally decided to replace the rear this year and we had to get the conversion kit to make it work with the old style front and the 5 button thermostat.

Do not replace until it dies. They are easy to replace. Less than a hour.