A comparison ages. Occupancy in a new winter, a second harvest, a revised municipal count — each of these can be set beside the same neighbour without inventing a new question.
Conditions
We only re-compare a study we ourselves drew. The reference set stays as agreed unless a neighbour has closed, merged, or stopped publishing. If the set must change, the work is quoted as a fresh study, not as a seasonal addendum.
What you receive
A dated addendum of a few pages: the new charts, a note on what moved, and a sentence on whether the earlier reading still holds. The original bound note is not rewritten; the addendum is filed with it.
Timing
Write when the new period is closed. A re-comparison started on half a year of figures will be marked as partial, and we will say so on the first page.
Fee
Lower than the first study because the neighbour is already chosen. Quoted per season. No standing instruction is assumed; you ask each time, or you agree a year of two sittings in advance.