I got my target card in January with a $2500 limit (at the time my highest limit). I use it regularly for around $100-$200 and PIF every month. I did try letting a small balance (under $50) carry over one month too, but up until now I'd had no love.
I've given it a lot of use for the holidays (around 10x my normal spend) and just opened my statement to see a $600 SL increase. Not a huge jump, but it's progress.