Coil packs how long do they last?

[986 Boxster]

2001 2.7L with 134.000km (83k miles) still on the original coils. I never change coils on a car unless they give me problems. I know that a lot car manufacturers recommend changing coils at 100k miles, but I`ve never done it unless I get a code that they are bad. Of all the cars I`ve had, I`ve only had to change one coil on a car with 366k km (227k miles).