I was just approved for a $1K CLI on my Capital One Quicksilver card, taking it from $25K to $26K! What is unusual is that my observations have been that Capital One has normally required moderate spending of the current limit to approve an increase, and this card hasn't seen the same level of spending that was needed for previous increases. I find this an interesting data point.
My Quicksilver card was opened in 2009 with a low $1K limit as a Platinum card. I had planned to use it from balance transfers but sock drawered it since the low limit wasn't useful. After the Quicksilver was introduced in 2013, I product-changed it and decided to try to grow it. It took a lot of effort with moderate spending and regular (soft-pull) CLI requests, but I finally grew it to $25K as of 03/13/2020. (See link with data points.) With the spending estimates I had calculated to get an increase, I decided that was enough, especially since my goal at one point was just to get all my limits up to at least $25K. I had better rewards cards and didn't want to work that hard to get another CLI with Capital One.
More out of curiosity, I hit the CLI button today. I've done that periodically just for grins the past year with denials. Today, they approved me for the $1K increase even though my activity on the card has been light at best. (Total spend for the past 12 months is about $676. No new activity was reported for 5/12 months. New charges ranged from just $76 to $133.) From my past experience, charging about 45% of the current credit limit seems to be the minimum for a successful increase.
I will note that I opened a "360 Performance Savings" (Online Money Market) with them and parked some significant deposits there. Since then, they've been treating me "extra-special" with lots of solicitations for opening a regular checking account, product changing my Quicksilver to Venture, BT offers, and several other things. I've had some cards with other lenders stay intact with little-to-no activity where I have active deposit accounts. While I didn't open the savings account for that reason, it does make me wonder how much other banking plays into decisions with them on CLIs, or even avoiding their CLDs they are known for sometimes.
The past 90 days have been quite successful for soft-pull CLIs! I started out the $15K approval for the AMEX Marriott card in November. With +$30K on AMEX Marriott; +$10K on Apple; +$8K on NFCU Platinum; +$1.5K on Citi-Costco; +$1K on Discover; +$1K on Capital One, that makes $66.5K in new credit with no hard pulls! 
Sweet! Thanks for the help along the journey, my friends.
Grats on your Quicksilver move up 
CONGRATS on such an incredible year for increases! Amazing Job!
Congrats on this somewhat unusual CLI and on all your other recent successes!
You are pretty good at writting an essay! )
Congrats on your Cap One CLI!
