This is an interesting statement contained in the NTSB prliminary
accident report of the SR22 that crashed in Florida this past January.

"According to maintenance records, the PFD had been replaced on June 4,
2004, at 12.2 hours, on September 14, 2004, at 55.2 hours, and on
December 20, 2004, at 80.6 hours."