The number bicycle repairs in the field depend on the quality of the bicycle components chosen and especially the quality of wheels. I don't use a narrow chain for 9-10 speed drive trains. I only use DT Swiss stainless steel spokes. Bicycle frames are usually high alloy steel for comfort and resilience. My current bicycle frame is a Columbus Nivachrome steel frame I silver soldered together 20 years ago.
I've heard to many horror stories with folks using Carbon Fibre parts breaking. Much of todays cycle parts are overpriced rubbish. I'm still a fan of square taper bottom brackets Campagnolo standards and 7 speed drive trains.

Finding parts is now getting quite difficult but there is NOS vintage kit, which is excellent quality. For example to replace the headset on my current bicycle

http://www.ebay.com/itm/Vintage-NOS-NEW-NIB-Shimano-600EX-HP-6207-BSA-BSC-headset-/391319158318