Partial Scans/Directory Watching?

[ratsupremacy]

Hi, just wondering if there's some sort of option to either watch directories (inotify, etc.), or do a "partial" scan that doesn't take a huge amount of time? I know "rescan" doesn't re-read every tag, but it still takes quite a while.

It seems a bit odd to re-scan everything in order to add a few albums.

If these options do exist, how do they work, and is there a way to tweak?