Most of our kittens will stay with us until they are 16 weeks old. There are several reasons for this. First, the kittens must be a minimum of 12 weeks to undergo a spay/neuter surgery. This still allows them time to heal in a nice quiet, familiar enviornment. Similarily, a kitten's vaccine schedule is very time sensitive and they need to stay with us to ensure they are properly protected from various diseases before venturing out into the world.
The other huge reason for us to keep them is to make sure they are properly socialized, and fully weaned from their mother. Kittens taken from their mom too early will likely exhibit several behavioral issues. A kitten should NEVER be rehomed at 8 weeks of age. This does not just apply to our kittens, but all kittens.
Once the time has come to take your new kitten home with you, a great idea would be to set up a 'safe' area for him/her. This space could be in a bathroom or a bedroom, should be quiet and include a litter box, bed, and food. Often little kittens can be overwhelmed with new places and people, and giving them their own space will help them to adjust. In a few days your new kitten will feel comfortable enough to come out and explore.
If there are other pets in the household please socialize slowly and carefully. Throwing two or more animals together can cause lots of unneeded stress and be a potentially dangerous situation.