I just got a increase on one of my cards last week. I have a few cards I use for different purchases. Never max them out and always pay on time. I've called to have them increase my limit twice (past 2 years), the last time they raised it more than I asked for. One of my cards already has a high enough limit so I haven't bother.
Edit: For clarification, the last increase I got last week I did not ask for, so 3 total raises on that card (2 I asked for).