The Challenges of Measuring Banknote Lifetime

Banknote lifetime values need to be treated with care because it is easy to form misleading conclusions. The biggest challenge is ensuring that a fair comparison is being made and that comparisons are made on representative data. The before and after scenarios should be like-for-like.

At a simplistic level there are different starting points to the measurement, so any comparison of note life should use the same point. Does the note life start when the banknote was produced or when it moves vaults or when it enters circulation? Is a banknote still considered to be aging if it is issued by the central bank but sitting in storage in the vaults of a commercial bank?

There are also different banknote lifetime end points. Mathematics can model the age at which a banknote is likely to have fallen below the acceptable fitness standard, but central banks assess each note themselves before it is declared as unfit.