mjhjmtu

I've just:

Does using noatime on modern Linux make sense?

and I'm interpreting the answer there as follows: "If you don't have applications that depend on atime's being valid, you don't need them."

Thinking about my home Linux system, which doesn't serve much of anything to anyone (and I don't use a local MUA, not that I'm aware of anyway), it seems to me like I can safely set noatime (and nodiratime). But maybe I'm wrong? Do some typically-installed apps use it still? I'm having doubts about this since I don't see why anyone would expect the OS to maintain atimes for everything just so that it can know the atime for a few files of its own.

Pragmatic answer: just use relatime - that way you don't have to know or care whether any apps you use rely on atime or not, and you won't risk breaking something that does rely on it that you forgot/didn't know about.

With relatime, the atime of a file/dir will be updated only if it has been modified since it was last read, giving all the benefits of atime without the performance penalty.

BTW, two of the most common uses for atime are MUAs (which you know about) and some programs/scripts that process files in an "incoming" queue check if the queue directory has been modified since it was last read (i.e. mtime > atime) to figure out whether there is any new work to do.