Xbox Timer allows parents to control play time.

Parents can use it to restrict children's activity time. As their usage time diminishes, "helpful notifications" will appear to warn young gamers that their session is coming to an end. At the appointed time limit, the tool will automatically turn off the console.

Sounds like a good idea but I wonder how many parents will 1) know that it is available and 2) be able to get and install and actually use it. Most parents have no idea how "those things" work and what can be done with them. For a lot of families, the kids know much more about technology devices than the parents do. Kudos to Microsoft for trying though.