phono stage break in?

This one is not a rebutal by any way, just a question:
Well...what about NOT using anything and just keeping the phono preamp on for a while. Does someone have any evidence that this by any means yields inferior results than buying a $20 CD ?

Nsgarch- thanks for your response. However, I am not sure that I agree with it, and I think that by just turning the unit on for as long as needed (without even an input cable plugged in), you are basically achieving the same goal...and, based on your rationale, you are actually "feeding" the preamp the weakest signal possible...allowing you to use higher gain.
I must say that these CDs always struck me as one of the most unessecery add ons that are out there.

Dan_ed, Nsgarch, Rauliruegas
I really do appreciate the time your took to explain it to me.

I used to be a firm non-believer in break in phenomena, until I recapped my preamp (ns-10). When I first got it it sounded awful, dry with decreased dynamic range. Over the next two weeks, it changed, but I was actually absent most of time and it was fed just statics from the cartridge...
Same thing goes for my new phono preamp.
Would an RIAA cd make it faster/better? maybe. however, The results that I got using the above methods were more than satisfactory to me.
As for the CARDAS sweep record, I am seriously considering buying it, so thanks for the warm recomendation!!