Thanks for the reply. I'm aware they are SPs, so nothing to lose. Why I'm posting is because I'm trying to gauge how likely it is of any chance of success. It won't necessarily change any decisions I make right now, but it's helpful to have in mind if there is virtually no chance versus a decent chance etc. I suppose I might make slightly larger payments if I really thought it would help, but I really don't want to otherwise as that's cash I could use other places where I know it will have impact on getting potential CLI on other cards (instead of just might).
I'm waiting to do an initial SP request until the account is three months old, and then a little longer to wait for the paying off of an AU account to be reported (so probably the end of April will be my first request attempt) 
@tricklemoo wrote:Thanks for the reply. I'm aware they are SPs, so nothing to lose. Why I'm posting is because I'm trying to gauge how likely it is of any chance of success. It won't necessarily change any decisions I make right now, but it's helpful to have in mind if there is virtually no chance versus a decent chance etc. I suppose I might make slightly larger payments if I really thought it would help, but I really don't want to otherwise as that's cash I could use other places where I know it will have impact on getting potential CLI on other cards (instead of just might).
I'm waiting to do an initial SP request until the account is three months old, and then a little longer to wait for the paying off of an AU account to be reported (so probably the end of April will be my first request attempt)
I would advice as @M_Smart007 suggested and make some large payments and I would not apply until you have had the card atleast 6 months or longer .
My theory on this, @tricklemoo, is that it might help but it may also depend on how long you carry it - and how much interest or BT fees you pay Discover. My card is my oldest currently-open card dating to 1993. I used it for some low five-figure BTs many years ago besides regularly using it in other periods for light spending. I've never put large spend on it. Over time and with relationship with Discover, it grew to $50K, although my income and FICOs had also risen. But I wondered if the earlier BTs had helped.
I remained "stuck" at $50K until I put some large short-term BTs on the card and got (2) small $1K additional increases. So my BTs might have helped ... but not much since in this situation they were only carried short-term. (The others I had were carried for a year or so each.) I'm not suggesting to pay fees or interest just to try for a CLI, but if you need to do so anyway it might help.
@tricklemoo wrote:@Jnbmom thank you- is there something documented/magic about 6 months versus 3 months or some other duration?
Most lenders have a minimum interval that they will consider a CLI, @tricklemoo. Six months is fairly common as a general rule-of-thumb and it specifically applies to Discover. So while you can always ask, they won't approve one unless the card is six months old or it's been six months since your last increase.
@tricklemoo wrote:thanks for the personal experience @Aim_High, interesting! Good to hear that with light spend you still managed to get up that high, though if the card is that old/you have that long of a relationship, not sure if that is the primary factor!
You're welcome, @tricklemoo. I imagine the long relationship did play a role, among other factors, in my ability to grow the credit limit. In the earlier days of the card, the ~1% cash back was very competitive if not industry-leading at that time, so it got more regular spending. And then the balance transfers I mentioned helped to build my internal credit history with them since they saw I handled my card responsibly. In later years, my credit limit has probably increased also due to much higher FICO, higher income, other high credit limits, and continuing to push for CLIs when eligible. (When it comes to CLIs, the "squeaky wheel" gets the grease; don't be shy about asking!) 
