Someone runs a report and notices a dimension called "Legacy Region" still showing up as an active filter option. Nobody currently on the finance team can explain what it was for, whether anyone still uses it, or whether it's safe to retire. This is an ordinary, common state for dimensions to end up in — not because anyone did anything wrong, but because dimension decisions get made once, quietly, by whoever needed that specific breakdown at the time, and rarely get revisited as people move on and business needs change.
Why Dimensions Accumulate This Way
Creating a new dimension in Business Central is fast and doesn't require much justification in the moment — someone needs to report on a specific breakdown, a dimension gets created, and it solves that immediate problem. What rarely happens is a corresponding decision, later, about whether that dimension is still needed. Dimensions don't expire on their own; they just accumulate, one reasonable decision at a time, until the total picture is a structure nobody currently understands in full.
Why This Isn't Just Clutter
Beyond the confusion of unexplained dimensions, excess dimension usage has a real, measurable performance cost — every additional dimension combination expands the Dimension Set Entry table, and reports filtering or summing across dimensions get measurably slower as that table grows. This is covered in more technical depth in a related performance article on this site, but it's worth knowing this isn't purely a tidiness issue; it has a direct, compounding cost on system speed.
How to Actually Clean This Up
Audit Actual Usage, Not Assumed Usage
Before deciding a dimension is dormant, check whether it's actually used in any report currently being run, not just whether it exists on transactions. A dimension with historical data but zero current reporting use is a genuine candidate for retirement, even if data exists against it.
Never Delete — Deactivate
Dimensions with historical transaction data attached should never simply be deleted; doing so breaks the ability to accurately report on prior periods. The safer path is preventing the dimension from being used on new transactions going forward, while preserving it for historical reporting on data that already exists.
Distinguish Genuinely Load-Bearing Dimensions From Redundant Ones
A useful test: for each dimension, ask whether removing it would actually change a decision someone makes regularly. Dimensions that pass this test are worth keeping and maintaining properly. Dimensions that don't — the ones nobody would notice disappearing from a report — are the ones worth actively retiring.
What a Clean Dimension Structure Actually Enables
Beyond the performance benefit, a dimension structure that only contains genuinely used, well-understood dimensions makes reporting faster to build, easier to explain to a new hire, and considerably less prone to the kind of "wait, what does this one even mean" confusion that slows down every ad hoc reporting request.
Where to Start
Pull your full list of active dimensions and, for each one, ask directly whether anyone on your current team could confidently explain what it's for and who uses it. Any dimension that fails this test is worth investigating for retirement — not because it's necessarily wrong, but because nobody currently understands it well enough to know whether it still matters.