Kits fail quietly
Expired, raided, and missing the thing you actually need.
First aid kits degrade in three ways: contents expire, items are taken for minor use and not replaced, and the original specification never matched the actual risks of the site.
The raiding is the most common and the least recorded. Plasters and headache tablets disappear steadily, and the kit that is opened in an emergency is missing exactly the ordinary items that were easy to take.
The remedy is a small separate supply for minor use, kept elsewhere, so that the emergency kit is not the convenient source. That single change fixes most of it.
Checks need a named person, a schedule and a record, and the record needs to be at the kit rather than in a system, because the check is done by somebody standing in front of it.
Contents should reflect the actual hazards rather than a generic list. A workshop, a kitchen, a laboratory and an office have different plausible injuries, and a standard kit will be wrong for at least two of them.
The other kit failure worth checking is accessibility rather than contents. A kit stored behind a locked cupboard, on a high shelf, or in an office that closes at five is unavailable in exactly the circumstances it exists for.