Replace A/C unit immediately?

[Jeremy Blevins]

Hey BP my wife and I just purchased our first duplex. We plan on remodeling the interior of both units. The roof and windows are already both fairly new however the A/C units are both roughly 30 years old. My question is, would you replace the units immediately even though they are working or wait until the due to replace them? We will have a home warranty for a year but I like the idea of just replacing them from the go so that we don’t have a surprise in the future if one of them go out. Thanks for any advice on this!