have dired always refresh on changed disk

[Emanuel Berg]

dired often tells me the disk has changed and I should
hit "g" to refresh the buffer.

Because dired knows it, it should be simple having it
always do it, automatically. (But: does dired *always*
know it?)

It could be an option as perhaps not everyone wants it
(?).

But I don't care for the status of the buffers that
aren't selected. Only when I select or open a dired
buffer, it matters to me if it is in synch or not.

The dired hooks I found are:

    dired-after-readin-hook
    dired-before-readin-hook
    dired-load-hook
    dired-mode-hook

- none of which seem to be suited (?) to do this in.

Can this be done easily or do I change the code?

-- 
underground experts united