While fitting my new front pads and discs(possibly the easiest i have ever done on any car 20 mins for both sides) i noticed the remains of an engine belt on the subframe of the car.

Appears its the air con belt which has snapped due to the tensioner for it sezing and rapidly wearing the belt away, more expense and time to change that, lovely

On the plus side, nothing else is affected so it can wait as long i can live with out air-con

Aghhh! So this is why you should run you air con for 10 minutes every few weeks then i guess...

well thats more to do with stopping the build up of fungus(yes, fungus) in your pipes and heater system.

I dont think you would be able to predict this, other than checking the quality of your belts everytime you open the bonnet, it is pretty obvious that somethings wrong as the belt that has snapped is really really worn shiny no writing visible, cords showing, whereas the other 2 are practically brand new, all writing visible etc

Air con = window down (unless your windows broke like mine)

Air con needs running at regular intervals tp prevent the seals from sticking and then getting damaged on start up after a long time. I'm sure there's a fungus issue as well but it's the internals that need regular attention.
Uncle Buck