Anywhere from 20 minutes to 4 hours....when I first got online and with the novelty of having endless porn piped right into my house, went 'till 6:00 a.m. ...that's from like 10:00 the night before (yeah....a little problematic).
Average....about an hour.
I'd love to get off this stuff. It's bull****. It wastes too much time. The longest I've gone cold-turkey was a month....a couple of times. But it's not like external addictions. The body isn't born needing to drink, smoke, or shoot up regularly, but getting horny...that's natural
Then again....it's just another chemical. The only difference is the brain is making it's own drugs. It's self-medication. It's emotional isolation/insulation.
It's somewhere to hide....hide from fear--or because of it... hide from failure--or the threat of it.
I've been getting much better at getting up and walking away...without ejaculating. I just get up, go to bed, or go outside, or post/write e-mails to friends. It's a good thing to be able to catch myself, and talk myself into walking away from it for the time being. It's getting a little better.