Caught a $4k problem before it became one, want to share what actually changed

Nothing dramatic here, just wanted to share a small win. Noticed the HVAC on one of my units was creeping up in age and had it inspected proactively instead of waiting for it to fail. Tech found a component that was about to go, replaced it for a few hundred dollars instead of the full unit replacement it would've needed in a few more months, probably during a heat wave, probably on a weekend. what actually changed for me wasn't luck, it was just tracking the age of what's in each property instead of only thinking about it when something breaks. Feels obvious in hindsight but it took me two properties and one bad year to actually start doing it.

Anyone else have a moment where getting proactive about something small actually paid off?