now that I am using PSE4 more, am interested what others do about files-
obviously keep a copy of the original, but after a bit of PS work with half a dozen layers and saving .psd (or .tif which now seems to be much the same thing) the original 6MP=2MB .jpg has grown to 40-60MB

my inclination is to compromise and merge most layers but save with one live for anything likely to be printed (say 15MB) as I find printing (usually for a greetings card) needs something a bit more saturated and contrasted than for on screen - and much easier to achieve this by adjusting the transparency of an 'overcooked' layer than messing with the printer colour management settings

(epson 1290)