The idea behind compressing old files is to compress files that you haven't opened in a long time so that you free up a bit of disk space. There's no point compressing anything other than files you don't use much, as the overheads involved in uncompressing negate the saving in disk space.. Think of it as a way of archiving stuff you don't use much.
To be honest, I wouldn't bother, unless you're really low on disk space
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS