It is ideal to have enough space so each of your child has its own bedroom. But what if you have just one bedroom and four kids? The best way out is opting for bunk beds that will accomodate all of your kids plus will help solving space issues.
So much room for activities. but little, individual reading/working nooks (for a tea house or library.) -- or just a space to crash/decompress/work in a different position. And the scene from step brothers makes it even better!