I have one that was opened in 1987 and still on my report despite last activity/closed in 1994. Though Experian shows a schedule when certain cards are scheduled to drop off from the report - looks to me they use 10 years as cut-off.

The 7 years seems to be used for blemishes - a friend had a couple late payments on her student loan and the blemishes stayed on her report for 7 long years despite the loan was since paid off.