Wise words indeed above re careful management of flying hours around the 150 hr / annual mark. Interesting you mention extensions... my frustrating experience suggests that succes there depends on whether or not you're one of the 'chosen few' with your engineer (!)
I have been subjected to the phrase "we don't give extensions for operating reasons" ... particularly galling when the engineers concerned are pretty awful at managing their own timelines / spares ordering etc etc etc... Only extension they'd give was to the calendar aspect (not the hours) due to their inability to get the previous aeroplane out on time. Great. And entirely different to my own ethos when I used to work as a professional engineer... but that was on HMFC's pointy jets!