I used to work in a humane society, I was known as the Cat Lady (sometimes with a 'crazy' put in there) I fostered baby kittens who had been brought in, until one of our regular fosters could take them. I fostered an adult cat who was having cage issues. (kept him for two months, my two ladies (both calico) were not happy) I took him back when someone wanted to see him for possible adoption. I'm happy to say that Charlie was adopted that day.
I do want to say that fostering is one of the greatest things sometimes. If you have a bit of room in your home and heart to take one of those animals who have been at your local humane society for even a couple of weeks it can make all the difference in their lives. Who knows...you may even find a new 'bestest friend' of your own.