When you are Pretty Sure of the answer, but you want to confirm becuase it'll Muck Up Important Things, you'd ask. Or at least, I would.
in reply to T.I.T.S. Or, Try It To See.
Sometimes you just don't have the time to understand the how and why of every bit of code you write. Eventually (or so you promise yourself) you'll learn, but the Boss needs the Answer now, if not yesterday.
For instance, my contribution to the CB today was "what is the size of an array?" If someone asked me that, I'd probably thwap them and ask them to look it up (half because I don't know) - but my question was only probing to find out if there is some obvious value that everyone knows and I don't. (For the record, I did Google :P it up before asking.) I distinctly remember reading about 10000 elements in someone's array on this site, and I also remember defining the number of elements in an array in C. The answer I got was something to do with vroom. It, in a strange way, reassured me that there wasn't a number one could/would throw at me. So that was not the bug I was looking for in my program.
Circular thinking, I know, but a whole bunch of us do it.
BTW, if whoever did reply to me in the CB reads this - thanks. :) I got DCed before I could notice your name, or reply, and throwing a generic thanks wasn't really going to help (or was it?)