How long is too long?
Of the 245 Boeing satellites that have been launched into service, 166 have exceeded their design life. That's more than two-thirds of the spacecraft built at the facility since the 1960s. A third of all satellites have lasted at least twice as long as expected.
so, 1/3 failed early for some reason (does this include launch failures?)
1/3 lasted somewhere between their "expected" service life and twice as long
1/3 lasted more than twice as long
The average of all that is only a little more than unity. Maybe as much as 50% more than the nominal life.
if you bought a car, or a washing machine, or a DVD player and it failed in 18 months, after a 1-year warranty expired, you'd reckon you'd been dudded.
Things should REGULARLY last ten times their design life...