just like the spark plugs, the coil packs don't age unless driven, so it's really not a matter of time but mileage.
The spark plugs should be replaced regularly, every 40,000 on your particular car '06 987). Other model years have different recommended service schedules..
Coil packs should be replaced if they generate a misfire or develop deep cracks of the exterior casing.
Happy Boxstering,
Pedro
Pedro Bonilla1998 Boxster 986 - 311,000+ miles:
[www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)
Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna