Remaining Useful Life (RUL)

Remaining useful life is the estimated number of years a reserve component can keep serving its purpose before it needs major repair or replacement.

A component due for replacement this year has a remaining useful life of zero. A roof installed 8 years ago with a 20 year useful life has about 12 years left, unless its condition says otherwise.

That last point matters. Remaining life starts from age but is adjusted for what an inspector actually sees. A well maintained roof may get extra years. One with early failures may lose some. This is the main reason a site visit improves a study.

Remaining useful life sets the timing of every expense in the funding plan. Shortening one large component by two years can move a six-figure cost forward and change the recommended contribution.

It should never be greater than the useful life. If an inspection suggests it is, the useful life should be extended to match.

Source: this definition follows the National Reserve Study Standards, published by Community Associations Institute (CAI), explained in our own words. State law can define the term differently for its own purposes.