Aftermarket, Field Service & Service Parts worked example

Spare Parts Obsolescence Exposure at 50% still-salable stock share: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop still-salable stock share to 50%, then walk the calculation through step by step. Estimate obsolete spare parts exposure from parts at risk per review cycle, review cycles, salable share, and recoverable disposition yield.

The inputs for this scenario

  • Parts at obsolescence risk per review: 85 parts/review (held at the documented default)
  • Inventory review cycles: 6 reviews (held at the documented default)
  • Still-salable stock share: 50 % (the input this scenario stresses; the baseline uses 70)
  • Recoverable disposition yield: 55 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Gross obsolescence risk = parts at risk per review × inventory review cycles.
  • Recoverable obsolescence exposure works out to 140 recoverable parts at these inputs, and this is the headline figure for the scenario.
  • Gross parts at obsolescence risk works out to 510 recoverable parts at these inputs.
  • Stock no longer salable works out to 255 recoverable parts at these inputs.
  • Disposition yield loss works out to 115 recoverable parts at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where still-salable stock share sits at 70% and the headline result is 196 recoverable parts, this scenario comes in 28.57% below the baseline at 140 recoverable parts.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to still-salable stock share, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes the salable share and disposition yield hold steady; in practice, the longer parts age, the lower both percentages tend to fall.

Results at a glance

  • Recoverable obsolescence exposure: 140 recoverable parts (headline result)
  • Gross parts at obsolescence risk: 510 recoverable parts
  • Stock no longer salable: 255 recoverable parts
  • Disposition yield loss: 115 recoverable parts

Run it with your numbers

  • To rerun this with your own numbers, open the live Spare Parts Obsolescence Exposure calculator, set still-salable stock share to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.