Day 22 / 30 · The upkeep calculator
Make maintenance part of break-even
An apparent per-use saving must repay setup and survive upkeep. Explore the arithmetic without treating a projection as an observed result.
A practice exercise · Examples are labelled; your entries stay in this page unless you choose to save or download.
Try it for yourself
Keep or clear my exercise
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Take it into your work
The default example reaches break-even at 20 uses. Actual savings and maintenance can change; a projection does not establish lasting benefit.