It also makes it more difficult to spot if one of your miners goes down, if each has a unique worker ID then faults are easier to spot from the Slush stats page and its much easier isolate/fix a problem. All the miners will also get work of the appropriate difficulty too.

Rascall

If you mine on a small pool (slush) then the daily and weekly "pool luck" is pretty meaningless. The only figure worth looking at is the 1 month "pool luck"  and even that needs to be looked at longer term.

just my 2p

Russell