When you have a customer scenario (i.e., someone whose machine you don't get physical access to), the only things that are "too much logging" are repainting functions and nearly anything called by them (which should be nearly nothing). Or other functions that are called 100's of times per second during operation (program startup is ok, though, to have 100's of calls to get/set routines logged because, in my experience, that's where most of the problems originate).
Otherwise, you'll just be kicking yourself when you're missing some key log point that would definitively tell you what the problem is on the user's machine.
(Note: here I'm referring to the logging that happens when trace mode is enabled for developer-oriented logs, not user-oriented normal operation logs.)
