Beginner's approach to laydowns:

First 20,000 hands - don't laydown enough
Second 20,000 hands - laydown too often
Third 20,000 hands - hopefully find a happy medium?

Rather than suggesting you leave the table when you've tripled up, I'd suggest be totally aware of any subconscious loosening up - the "oh I can afford to see this flop" or "I am the big stack, let's try to bully my way to this pot" effect.

Actually, tightening up is a problem too, and one I suffer from sometimes. I get miserly - I see my lovely big stack and I metaphorically fold my arms around it - I don't want anyone else getting their hands on my cash. At this point I usually leave the table because I know I've stopped playing for value.