At 100K, the cam follower should definitely be replaced if not already. It's also the mileage at which cam chain/VVT phaser wear start to rear their ugly heads.
Not wanting to inject some fear mongery, but that end of the engine has the potential to cost major £££s if ignored, so listen out for any clattering and unhealthy noises.
The PCV, diverter valve etc etc affect the performance and drivability almost immediately, so are easier to detect than the above naughty b'stards.
I doubt you have too much to worry about on a standard car, but if looked after, these engines can do 200K easily.
Don't ask how I know about the HPFP/VVT end of the engine
That little lot is £700 worth.