Generally speaking, Lifecycle Prefixes mean that when something is no longer in use, a tag such as amenity gets changed to disused:amenity. That should be straightforward, but sometimes disused=yes creeps in.

This example overpass query for nwr["amenity"="fast_food"]["disused"="yes"]({{bbox}}) finds a couple of examples. In these cases we can have a look at the tag history and (as seen in the picture at the top) notice that the FHRS ID changed recently, and the disused=yes actually corresponded to the name of a different business on the same site (in fact that that one has the full set of such tags: ["amenity"="fast_food"], ["disused:amenity"="fast_food"] (which don’t make sense together) and ["disused"="yes"]. In these cases you can often look through the tag history and see what the current status is supposed to be; if the last changeset comment was “this has now closed” it’s fairly obvious.

So does disused=yes always mean that someone has forgotten to change something to a lifecycle prefixed version? Well, maybe not. As an example, what about this former quarry? It’s not used as a quarry any more, but it is still a very big hole in the ground, so it makes sense to show it as such. Maps that I create distinguish between operational quarries

and historical ones

so including disused=yes in the latter category was straightforward.

What else might disused-yes occur with?

Quite a lot of the landuses don’t need any change at all. For example landuse=brownfield; disused=yes is something that people have tagged, and landuse=grass; disused=yes is also around; it usually means that something else (perhaps no longer tagged!) is disused.