I wasn't asked, but thought I would answer anyway. I have 802 cards at the moment. 147 are suspended.

I first became aware of SRS in 2005 or so, and I started using it in fall 2009 for a mechanical vibrations course. There was a considerable speed advantage on the exams if you memorized the Laplace transform table and a number of differentiation and integration rules. After that course I fell in and out of the habit. I started using Beeminder to force myself to do my reviews and add new cards regularly in May of this year, and I've added the vast majority of the cards I have since then.

Beeminder and Anki are an amazing combination. I highly recommend this if you are not good about regularly reviewing or adding new cards. Right now I review daily, and I can earn a 1 on Beeminder if I finish all cards (including new ones) or spend half an hour reviewing in total. An average review involves around 50 cards and takes roughly a half hour (the time limit is mostly for when I am very busy, and it is rarely invoked).