Valve Adjustment - The When???
 

How does one really know when they have to adjust the valves?
I am a little paranoid I think but:

It's been about 5000 miles.
At start up the engine sounds a little clattery- I think..

I was going to do my first drop this fall and do it with all vac hoses etc.

What do I really need to watch and listen for.

154000 km
79sc
starts great
idles great
seems to run well but what do I know.

5,000 is about the right time. If you can hear them (clattery), they are on the loose side and that is good. The usual pattern is they get tighter with wear and damage can occur if too tight. Probably safe to wait till fall if you're going to do a drop anyhow. It's not necessary, but easier for sure....

There's no harm in checking them. It'll only cost you time and a new gasket/hardware kit. It'll also help you get familiar with the procedure and give you an opportunity to compare the current settings to the current "clackity" sound. The more times you do it, the easier it is to tell when it needs it.

every 20.000 km as instructed by PAG.

At startup they tend to sound like that, adjusted or not. Should go away when at operational temp. What about when its fully warmed up?

If you are inclined, go ahead and check them yourself. Its a fairly easy job, albeit time consuming, but very rewarding. Believe me, I am frigging doc. Had no prior mechanical experience before I joined these beautiful wackos and they very patiently taught me the procedure. Get the Bentley manual and Wayne´s 101 Projects for your Porsche 911 and go for it! :)

Search for "Backside Method" and you can check them without having to change their settings...

Wayne's book says Q 10000 miles 1979-on, Q 6000 miles pre1978 (pg 58).