Valve Clearances - How often to check?

Hi Guys,

Just been reading a 4WD Action mag as it had a write up on the TD42.

In a section they titles "Deal Breakers - When to Walk Away" they note that valve clearance should be done every 20k.

I have done a bit of trawling on here and on google and though I can see various discussions on the subject of clearance amount, I cannot find anything on when to do it. The write up notes that you should look at the last service histories to check it is done or ask the guy if he knows the clearance of the top of his head ( buggered if I did until recently and after a bit of reading)

So can anyone suggest how ofter it should be checked and really is it a deal breaker if it hasn't been done or you cannot confirm it beign done every 20k?

Cheers guys

It says 20k in the manual

mines been running for 300k and clearance has never been touched ... was gunna have a look see soon.

Wow. Every 20 thou. Does that include the TB45 as well? I've had mine for at least 20 now and its getting louder than usual.