“Others'” is correct when we want to show that multiple “other” people or things share the same common ground. It’s rare to see on its own, and we usually require a secondary plural noun to help explain it.

A: When it’s clear that the “others” are more than one, then our usual plural possession rules kick in – with the apostrophe after the S. For example: “These two teams had scored more points in the season than all the others’ scores combined.”

So if you say “each other’s” it has an apostrophe before the S? Not each others’ or each others? A: That’s right. In this case “each other” is treated as a singular entity – despite the fact that there are clearly two parties involved.

In order to pluralise a regular noun all you usually need is to add an ‘s’. Therefore, the correct version is we are open Mondays to Fridays. Similarly, apostrophes are not needed in abbreviations like DVDs or HGVs. This same rule also applies when using numbers like the 1920s or the over 60s.