On the subject of doing app-o-rama's all in one go and the benefit of it, here is what I learned based on Equifax only (I don't have TU online, so can't judge immediate impacts etc.)
As soon as a hard credit check has been performed for 1 card, the second after it shows up on your credit file and subsequent checks of other financial institutions know about it. It does not take them 24 hours, it takes 1 second/instant.
Traditionally it is believed that doing 1 check per week shows one is a credit seeker, instead of doing 4 on 1 day where one would not be seen as a credit seeker. I’m not so sure.
I've been declined on a number of occasions, and the reason was not credit serviceability of past known credit or income, but either not enough time between credit checks or unable to assess credit serviceability of the recent credit checks (i.e. that same day, whether they’re approved and for how much). Some cards apparently want to see 6 months between apps, others at least 3, others no credit checks that same day, others don't care. I think it is also safe to say in general a very high end or highly sought card or certain promotions will be more likely to require 6 months, medium cards more likely 3 months, etc.
In our app-o-rama's it would be useful for people to post their list of straight accepted, call-in accepted, declined and reason, AND order in which applied.
It might be useful to start app-o-rama's in order of card requirements rather then in order of card perks wish/importance. True, they often go hand in hand, but not always, and importance of a card varies by personal preference more then by FI requirements to obtain the card.
From experience, I would start with the high end cards of C1 OR BMO OR Chase (I've only ever had 1 of them approved in 1 AoR, but 3-6 months later have had the other fly through when done in first position), then TD, CIBC, Scotiabank, etc. Then the lower cards such as retailers.
Having said all that, I have to say that my Equifax score has dropped less with spaced out apps then with AoR's in 1 day. Over 1 week following the AoR of 3 Equifax cards in 1 day, I'd see my score drop 3 times totalling 8 to 10 points. When spaced out, it would be dropping for every application between 0 and 2 points.
Spacing out applications to 1 per week does have the limiting effect for higher end cards that require 3 to 6 months of no checks though, and it is more efficient to do everything in 1 go. So I’ll keep doing them all in 1 day I think rather then what I did before to space them out. The apparent 3-6 points difference is not the world, but I wonder how FI really see/interprete AoR in 1 day versus spread out.