Teens and adults with Down syndrome tend (like many of us) to like doing things a certain way. And, in actuality, it is understandable. Once they have learned and accomplished a task, why in heaven's name should they exert themselves to do it in a different manner? The answer is, of course, that being "locked" in a certain behavior can often be incapacitating.
So, to those readers who have younger children with Down syndrome, try to introduce variations occasionally into the way things are done. Breakfast menus can occasionally be a bit different. The child can get dressed in a different room, outfits that are usually worn together can be "mixed and matched", etc.
One of the most important items to introduce flexibility in is the house one sleeps at. In an emergency situation at whose house would your child sleep? If at all feasible, try and have him sleep there once in a while, as a vacation. Ricki has been very reluctant for me to not be on the computer (in her room) as she goes to sleep. So the malfunction of my computer (and subsequent composing of posts on my son's hardware) has been an excellent opportunity to alter the situation for her. And I hope to do this on a more regular basis (although through choice, not necessity…).
So try and institute some variations in your child's life. It may save you a lot of problems later on.