Pierre,
You wrote:
WHY? Over time, it makes absolutely no difference on the exposure, none whatsoever.
Scenario...
I have the following categories in my eBay Store, well actually, I don't have any items as store items, just BIN - GTC...
BOLO TIES
BUSINESS CARD HOLDER
CHARM BRACELETS
COPPER & SILVER CUFF BRACELETS
COPPER CHAIN BRACELETS
COPPER CUFF BRACELETS
COPPER RINGS
EARRING & NECKLACE SETS
EARRINGS
GEMSTONE BRACELETS
KEEPSAKE BOXES
LETTER OPENER / BOOK MARK
LOCKETS
MAGNETIC JEWELRY
MONEY CLIPS
NECKLACES
PILL BOXES
SILVER & COPPER BRACELETS
SILVER & COPPER RINGS
SILVER CHAIN BRACELETS
SILVER TRINKET KEEPSAKE BOXES
STRETCH BRACELETS
STUD EARRINGS
WATCHES
OTHER
Ok, let's go on the premise that all of my Bolo Ties are ending on day 12. All of my Business Card Holders on day 13. All of my Charm Bracelets on day 17, all of my Copper Cuff Bracelets are ending on day 21, all of my Trio Charm Bracelets are ending on day 23, all of my earrings are ending on day 28 of each month. Renewing on that day of the month because they renew every 30 days....
Would it not be smarter to have 1/3 of my Bolo Ties ending on day 12, the other 1/3rd ending on day 20 and the rest ending on day 30? Same thing for all of my categories? That way not all of the bolo ties will get max esposure at the same time, they would be spread out during the month.
We all know that BIN items are interspersed with the Auction Item listings, but we also know that if the BIN items are within 1 day of renewing, they show up on the first page of a best match search. Depending on the category of the item being searched for of course. If the item being searched for is quite popular and a lot of sellers are listing similar items, then your listing might not show up on page one until 12 hours or less before scheduled renewal date/time using the GTC format.
I think I would like to have several of my 650 listings on eBay coming up for renewal within days of each other, but several from each category, spread over the 30 day period. This would allow for max exposure for all of my eBay BIN GTC listings.
(ie) 4 elements bolo tie renewing on day 2, black bear bolo tie renewing on day 5, angel gold reflection earrings renewing on day 2 as well, but my dragonfly gold reflection earrings would be renewing on day 5... You get the idea, at least that way I would have several of my products renewing and getting top exposure each day of th month. Hopefully, that would draw traffic to my eBay Store, and although they might not want the dragonfly gold reflection earrings, they might want the Hummingbird gold reflection earrings, which they would find at my eBay Store...
I think this is a sound approach...
Comments anyone?

"If we had no winter, the spring would not be so pleasant: if we did not sometimes taste of adversity, prosperity would not be so welcome."