Debt dissappears from Credit Report

I think a creditor has to renew the item on the report every so often. I think many creditors post information at least once a month based on payment history and what not. For example, if you had a current credit card with a balance of $1500 on it then your report would reflect that exact balance. If you paid $500 of that balance then the CR would be updated to reflect the new balance of $1000. I don't know what the minimum time frame is but if they did not meet it then it would fall off the report I believe.

Another option is the debt was paid and they quit reporting it. Also the creditor could have sold a bad debt to a CA and the CA has not gotten around to reporting to the CRAs.