The aggregate pain and aggregate loss of using cash for transactions in a credit-card dominated world is much larger than the concentrated pain of replacing a credit card once a year. I make significantly more than $30 here and $20 there on rewards - on the order of $500+/year

Sign up for Mint, and quickly scan all of your transactions on a monthly or bi-monthly basis. It's a good idea anyway, so that you can easily account and keep track of how well you're doing at saving.