I went 2000 jumps without a malfunction, then had three this year, two of which were tandem line-overs. As you collect replies, you might want to distinguish between aggravations like line twists (which occur every 4 or 5 student jumps, especially on Cat C and Cat D jumps), and malfunctions requiring reserve activation (every 300 to 1000 jumps, based on the replies you've received so far). Mark Baur