It will all depend on certain factors...style of beer, type of yeast, how much yeast you pitched, fermentation temp...
With that said, I will not even look at my beer until 2 to 3 weeks. You will need to take gravity readings to actually tell if it is done. If you bottle after 7 days without checking gravity, you will have no idea if it finished fermenting or not. If it hasn't finish and you bottle...you will have the neighbors calling the cops because of your bottle bombs.
Bigger beers you will want to let sit longer. Lagers will also need to sit longer.