A good driver with appropriate clutch control can get many miles out of a clutch. On my van I got 220000 out of the original clutch and even when is amazingly high I still drove it for a year or so.
A clutch needs to be replaced in only a few situations really. When doing an engine overhaul a new clutch is advised. Most good drivers will experience a failure in the clutch bearing before the friction material slips. Gearbox leaks can or contaminated friction surfaces can cause a clutch to slip too.
A clutch is in a way like a brake disc, if you're gentle it will last a lot longer. Even the best driver will eventually eat through a clutch. If your clutch starts to slip replace it or it could damage the flywheel which can be hellishly expensive even in a small k11. You'll know your clutch is slipping if the revs spike, or if the car is in gear with the clutch up and not moving.
You can test the operation of the clutch by putting the handbrake on hard, putting the car into second gear and bringing the clutch slowly up while applying more acceleration respectively. If it stalls, that's a good sign and your clutch is not slipping. If you can release the clutch and it's in gear but not moving then you should replace it when convinient.
If it breaks and your stranded you can put the car into second gear while the engine is off and hold the key on until the engine eventually splutters into life. You can't change gear but you can at least limp home with the hazards of shame lol.
You'll probably find its fine, my k11 has had a high clutch for the last four years... still not slipping. I expect the bearing will eventually explode and I'll have silver maltesers in my bellhousing before the friction material runs out.
With a good socket set, breaker bar and good quality axle stands... a clutch swap is an achievable but difficult DIY job. Not for the faint hearted or disorganised!
