Own two properties built the same year, early 90s. One I gutted and renovated three years ago, everything's basically new. The other I bought as-is, and as far as I can tell most of the original systems are still in there. been using roughly the same reserve number for both because they're the same age on paper. but that's clearly wrong, the renovated one probably doesn't need serious attention for another decade, the other one could need something any month now.

Feels obvious writing it out, but I think a lot of people (including me until recently) default to treating property age as a proxy for system age, when they're often completely different numbers. Anyone else catch themselves doing this? How do you actually separate the two when budgeting?