Post History

## Argument against

Quite simply, none of the available reactions has a *clear and pressing need* for such a marking.

### "Works for me" can be directly contradicted

The only good reason to mark a "works for me" reaction as "stale" is because the solution is now obsolete - and there is already a reaction explicitly for indicating that. We don't have to predict a timeline for a hypothetical Python 4; *if and when* it happens, we can mark answers that are 3.x-specific *after determining* that they are 3.x-specific (while leaving alone answers that *aren't* affected by the version bump, but are just as old).

### "outdated" and "dangerous" tags don't go bad

As already noted.

If a technique is outdated, it can't *stop* being outdated.

If a technique is dangerous, it is extremely unlikely to become safe *automatically*; even if new library support appears, the answer will probably have to be edited to take advantage. It would be incredibly poor practice on the part of e.g. a library maintainer to secure a fundamentally insecure technique, years later, *and reuse all the same names for it*.

Even if it did happen that version X of a library makes previously-unsafe technique Y safe, with no required alteration to the code, *the answer is still in a sense outdated* - because it doesn't account for the library version required for security (a version number that was unknowable at the time of writing).

*If an answer is edited*, years later, such that it goes from being outdated or dangerous to not being thus, then that in turn can be disputed by adding appropriate "Works for me" tags.

### "interest" becoming stale isn't relevant

Either the site went live, in which case there's no reason to care about book-keeping on the process that got that far; or the proposal has been in discussion for so long that it's probably time to face reality and reject it (probably without prejudice); or else it's one specific user who has reconsidered the proposal and *should be responsible for actively retracting* the reaction.

## Argument in favour

Because answers do get edited in ways that could immediately and directly invalidate a reaction, and because people do leave communities over time (and therefore could leave a reaction and then fail to see an edit that invalidates the reaction), and because sometimes people will just stubbornly disagree that their reaction is invalidated: I agree that we should at least be able to see the dates for reactions. Expecting a mouseover might be too much; I like OP's idea of reduced saturation for older reactions - but instead applied to reactions where *all* of the following apply:

* the question has been edited;
* the reaction was made before the most recent edit;
* the most recent edit is older than some time threshold (either configurable by community, or dependent on the community's level of activity);
* the reacting user has been relatively inactive since that edit.

Mouseover guidance would suggest something like: "it's possible that the reacting user hasn't fully considered edits made after making the reaction".