The real cost of ignoring error messages
Most teams know this matters. Fewer have decided who owns it. Nobody bills you for neglecting error messages. The cost shows up somewhere else.
Consistency is the quiet half of design work: it rarely gets complimented, and its absence is noticed immediately. The failure mode is not doing it wrong, it is doing it once and assuming it stays done.
Where the cost lands
- Time spent on work that should not have been necessary
- Enquiries that quietly never arrive
- Say what went wrong and what to do about it
- Rework, once the problem is finally visible
Never blame the person reading the message. The cost of getting this wrong is rarely visible on the day it happens. The practical test is whether someone new to the project could tell, in a minute, that it had been handled.
Making it stick
Put the error next to the field that caused it. In practice this is a scheduling problem more than a technical one. Doing this properly once is usually cheaper than doing it approximately three times.
The short version
The measurable part of design is whether people can find what they came for and act on it without hesitating. Three things worth confirming about error messages before you move on:
- Someone can say what the current setup is without going to look
- Say what went wrong and what to do about it — and you know whether that is true here
- There is a way to tell whether the last change to this helped
Most of the value here comes from doing the first two things, not all of them.