in online chess .. how long do you analyze your moves specially in complicated

5 minutes on average here on chess.com. Probably 30 minutes max. On other sites (or USCF CC) where I take the games a little more seriously I've analyzed for a couple hours.

In complicated positions, usually about 5 to 10 minutes. I must admit that a majority of my blunders come from under analysis or moving too quickly. I don't go much deeper than 2 or 3 moves for each candidate move or opponent's threat and this is probably a weakness in my game.

A good question and a difficult one to make. I would strongly recommend "how to find a chess move" by Solits which is about this very subject.

Pfren's comment is tongue in cheek but read the book and you will get the  humor.

I used to spend so much time and energy on complicated positions that i would have chess dreams ("knightmares" if you will).   Maybe that's why I haven't played online in months...... Probably having all 7 chess sets out exploring different lines for 1 game was a bit obsessive.

+1 :)

Usually a few seconds, never more than a couple of minutes. I didn't realize people take online games so seriously that they actually set up boards to analyze different lines. What else do they do, have a computer help with a move? 

Sometimes I will look at the possibilities for days. I will often leave no stone unturned, especially when I don't see an obvious move to make, or if I am in trouble. I will look for the best way to get rid of a piece I am sure to lose, or I will sometimes find a clever way to stymie a steamroller of an attack.

Haha! I've never even used one board to analyse different lines, though I do have an ulterior motive anyway: I try to go through the lines in my head as much as I can, to improve my visualisation skills. If I really care about winning the game, I'll use the "analyse" feature on chess.com and go through a few lines.

I make most of my moves after 1-5 minutes of contemplation/analysis, but sometimes will take up to 20mins. Any longer than that and I usually take a break and have a look at it later on.

I think it's usually an either/or situation.  People who take the time and trouble to set up multiple chess sets and obsessively analyze games usually have enough respect for the game not to cheat, but the periodically published "dishonor roll" of suspended members certainly shows it happens.