How long do you wait?

I just want some opinions on how long you should stay at an on-line table in Limit hold'em (regardless of limits) when you're not getting a single playable hand? For example, you sit down at a table and from your very first hand, you just get garbage every hand. Not a single playable hand. How long to wait before moving on to another table?

[CardSharpCook]

I usually tap the computer screen 3 times, stand up, spin in a circle twice, sit down, close my left eye for one second and then say, "Yo!" It usually does the trick.

I would sit up as soon as the fact that I'm getting no cards that I would normally play in the given positions starts to affect my play. This means as soon as I see that I'm playing crummy cards because I'm getting bored is when I'd quit and do something else for awhile. Also, this post does not belong in this forum--mods please let me know but maybe this is poker theory???

[goofball]

AK-

I wait until I'm getting crushed at that table. Bad cards doesn't hurt your table image, and table image is the only reason to chagne tables. If it truly is just bad cards then it's an issue of discipline if you feel you can't play well while running cold.