I don't read the manual unless I come across something I can't figure out in five or ten minutes. Then I check the table of contents and try to skip straight to the part that will tell me how finish what I'm doing. Otherwise, manuals go too long on boring obvious stuff and not long enough on the complicated problems that people actually run into.

Depends on what it's a manual for. For software, generally no. On the other hand, I will look up how-to guides and the like when I don't know how to do something with Linux.

I usually will use the manual to assemble the item if need be or if I have a problem in the setup. I do keep all the manuals of major electronics or such things in a drawer just in case.

This reminds of a time when I did not read the manual and should have, I used our self-cleaning oven for the first time. I failed to read that you should ALWAYS scrape down the insides of your oven before using the self-clean option. Needless to say, I was on hold with Whirlpool while flames were shooting out the cracks and cevices of my oven. It had locked automatically until the cycle would finish and the oven cooled, so there I sat wringing my hands. I thought it was going to burn my house down for sure.

ALWAYS READ THE MANUAL!