The 30-day limit is only for (some?) Wikimedia wikis. On very low-traffic wikis it can go back many months. So therefore it would be best not to include a number of days. Maybe change "all" to "all available changes" or something else that makes it more clear.

It could be "all ($wgRCMaxAge)" i.e. "all (30 days)" in the example: it's short and always works.

Yes, but $wgRCMaxAge is set in seconds so I suppose you could end up with "all (98.7 days)" or something.

(In reply to comment #3)

Yes, but $wgRCMaxAge is set in seconds so I suppose you could end up with "all
(98.7 days)" or something.

Is it impossible to do a division as in r26591?

Patch submitted to gerrit by Luis Felipe Schenone as Iffcbc837.

Discussion in patch review is whether this is an improvement in usability and clarity or not. Further input welcome.

To me it is pretty clear that displaying the number of days, rather than "all", is much clearer and thus an usability improvement. What does "all" mean? All the changes in the article? All the changes in the article since the user has been watching? Both interpretations would make perfect sense, and in fact they are the most natural to me. But it means neither: it means all the changes since the max number of days that that particular MediaWiki installation takes into account! And that varies per installation. So showing the actual number of days seems a lot clearer, doesn't it?

And no, I cannot provide any user tests that prove that this way is clearer, as Siebrand asks for, but I think that Nick Levinsons experience, plus the above argument, should suffice.

I think the best path forward here would be to just change the wording from "all" to "all available". The actual number of days could follow in parentheses, but I'm not sure about this.

(In reply to comment #8)

I think the best path forward here would be to just change the wording from
"all" to "all available". The actual number of days could follow in
parentheses, but I'm not sure about this.

+1, without parentheses.
I understand the original concern but the simplest solution is the best.

The current patch gives too much detail, and it acknowledges it by rounding the number of days. The upper limit only has a technical meaning, not a practical one: only rarely the user remembers and desires precisely 25 or 30 or 85 days timespans; usually you either want some common "human" timespans or just everything you can get.

Notice how Special:RecentChanges allows to filter by 1 | 3 | 7 | 14 | 30 days. It doesn't say: 1 | 3 | 7 | 14 | all available. And why would it? It would be confusing! Putting the actual number of days available would be the simplest, most natural, clear and unambiguous solution.

Change 38743 abandoned by Luis Felipe Schenone:
(bug 26022) Improved the watchlist UI

Reason:
Master has grown too different from this branch and I don't know how to solve it. Better to start a new change for this bug.

https://gerrit.wikimedia.org/r/38743

I've started a new patch set at https://gerrit.wikimedia.org/r/163142