@slither43 “ … I'm curious...if someone wanted two different Chase cards which served different purposes, what do you think an ideal waiting time between apps should be?”
I have been approved for four Chase cards in the past twelve months with no subsequent cancellations, so here is some recent data on multiple Chase apps.
I purposefully waited about 3-6 months on average between card apps because
(1) I needed time to make the spending limits on the SUBs on my new cards and
(2) I didn’t want to look desperate like I was applying for a bunch of new cards all at once.
It appears that strategy was successful.
I applied for the CSR first, since it was the card I most wanted. I also decided on the others more after the fact, as I looked at Chase cards and the synergy I could create by using different cards in their system and combining points with the CSR, which I now had.
I waited about six months between the CSR and INK Business, but that was also a business card, which is processed by a different branch in Chase. I then waited about two more months to apply for the Freedom and then a little over three months to apply for the Marriott.
Approval Dates below for Data Points:
Sapphire Reserve 05/06/18
INK Business Preferred 11/30/18
Freedom 01/29/19
Marriott Bonvoy 05/01/19
*Note: I already had an older Freedom Unlimited, so now I have the "Chase Quadfecta".
(I plan to downgrade my Business Preferred to the Business Cash later.)
Plus, I have the Marriott Bonvoy card.
(Mod cut: links to that site are not allowed on myFICO. - KiB)
Just giving an update... received my card in the mail on yesterday (Saturday) and made a small purchase on it to make sure it works and I'm stoked!!! Just a question to the community: If I understand correctly, with Chase I make a purchase and then PIF when it posts to get them to report immediately to the CRAs right??? 
“Most people work just hard enough not to get fired and get paid just enough not to quit.”
