Anyone actually track cost per system, or does everyone just lump it into one mainten

[Giuseppe Cavucci]

Curious how granular people actually get with this.

Some of the replies on my last thread here got me thinking. A few people track age and remaining life per system (roof, HVAC, water heater, etc.) and set aside a specific amount for each one. Others seem to just keep one general "maintenance/repairs" bucket and don't split it out further. 

If you do track it per system, do you actually update the numbers over time (like when a component ages another year, or after a repair), or did you set it once and mostly leave it? And if you don't split it out, has that ever bitten you, like two systems needing replacement around the same time and the general bucket not being enough to cover both? Genuinely trying to figure out if per-system tracking is worth the extra effort or if it's overkill for most portfolios.