I wasn't going to do a thread on this one, but on second thought I considered that the data points might be useful to some and with a gentle nudge from @Remedios here I am. 
Anyway, my previous credit line was $10.7k, and my last CLI was on June 29. Exactly six months would be Saturday, but today is 180 days so with a little encouragement from @K-in-Boston I gave it a whirl and Citi was agreeable:
This account has seen exactly one charge in the last six months (a bag of ice), so Citi definitely doesn't seem to be concerned with usage.
The card was a Diamond Preferred up until a few months ago, when I called and requested a PC to a Double Cash, as well as an APR reduction. It's still 20-point-something, but at least it's better than it once was (it was opened at the highest APR).
I'm not overly concerned with the APR, but like most people I prefer lower when possible, so I'll probably call them again in the spring to see about getting it lowered again. For some reason they won't do reductions for me over chat... I'm always told to call. ¯\_(ツ)_/¯
Anyway, the card was opened in 2016 with a credit line of $4k, so it has grown nicely. 
Addtional data points: minimal HPs, score 780-ish.
Again, shout-out to @K-in-Boston for giving me the nudge to give it a try today. 
Congrats and you deserve ALL of the credit. I just peer pressured you into asking today instead of Saturday.
@K-in-Boston wrote:
Congrats and you deserve ALL of the credit. I just peer pressured you into asking today instead of Saturday.
LOL!! Thanks, and I would say this is a good example of positive peer pressure!
Congratulations!
No credit news is good credit news!
That bag of ice sure did cost them
Congrats my friend.. You are an inspiration to the whole forum you can actually garden unlike myself and many others 
.. It shows it does pay off!
@CreditCuriosity wrote:Congrats my friend.. You are an inspiration to the whole forum you can actually garden unlike myself and many others
Thanks so much, my friend!
I agree... gardening definitely pays off! (Of course we all know I have my 'moments of weakness' as well, LOL!)
@trusty wrote:Congrats!
Did they pull a soft or hard inquiry - with which bureau?
It was only a SP. I'm not sure which bureau, but there was no delay at all so I suspect they used one they already had on file. If I had requested more it would have been a HP.
@Remedios wrote:That bag of ice sure did cost them
I know, right?
I actually made that purchase just a couple of weeks ago to make sure the account wasn't closed for lack of use, since the last time I used it was back in the summer.
It's hard to make a case to use a 2% card when I have a 2.5% card as well (USAA Limitless), although if I find myself buying something that could be eligible for Citi's 'Price Rewind' that might motivate me.