I'd say I'm pretty thorough, but still learning... things like the fact that you must never trust anyone else's word that a thorough preflight was done, no matter how much you trust their judgement. Also, I've learned that sharing preflight duties with one or more other people is not necessarily more efficient, even though it might seem to be. You're better off having each person do a full walkaround, if they feel like it. Two passes, if you will.
Obviously, when a glider is being flown 20 minutes to an hour or so, several times in one day by multiple pilots, we don't do a complete walkaround for each flight. But re-staging provides some opportunity to look closely at some things, and before every launch we do a proper control check.
On a power flight with multiple stops, I won't do a complete preflight at each stop, but certain things will be checked: oil, fuel, lights maybe, tire pressure and condition, and checking for leaks or damage. If I'm not the PIC or even flying on that trip at all, I will do at least a cursory walkaround on my own. So far I haven't offended anyone doing that, but if and when I do, they can go cry for all I care. "Pride goeth before a fall"... if anyone wants to do their own preflight before they fly with me, I'd welcome that.
Runup: first flight of the day, any time fuel has just been added, or if the airplane's been sitting unattended for a while.