How to test a clutch?

[type-r]

Going to view a 997 and wanted some advice on the best way to test a clutch. There seems to be various different ways to do it such as running in 30 mph and then putting the gear into 5th/6th and looking for linear revs as the car accelerates. If the revs go up but the car doesn't accelerate to match the revs, clutch is on the way out. Another suggestion I have seen is starting the car, putting it in 3rd gear and try to pull away. If the car stalls = sign of good clutch. If it moves = clutch slipping. The final suggestion I have seen, is that if the clutch feels firm to press in, sign that the clutch is on the way out. Also seen another suggestion around high biting point. With so much info, is there a definitive way to test for a wear on a clutch without obviously dismantling it.

[type-r]

Thanks for all the replies, useful info!

OlberJ - that is also good to know. I think if the clutch shows a minimum of 20% life, that will be good enough for me!

Cheers.