that would explain why I don't get on with the one button design. Now I know the design is for apps to rot away in the background I'll just keep an eye on the resources management instead of trying to close stuff I'm finished with.

I was at a MS event where one of the tech envangelists for W8 did say that users don't actually need to close W8 apps as when they go into the background they pretty much stop using resources. Essentially the apps suspend. Because of this they expect all W8 apps to be left running (of course this is not the case with anything that runs in the desktop mode).

There are of course exceptions - emails will continue updating, software updates will carry on, etc. But, these are all done via stubs rather than the full application.

He was wrong then as anyone using a WM phone will tell you. You do get better battery life if you totally close apps.

He may well be wrong but that is the way MS sell it to their customers.

That is the theory of course, but misbehaving applications will still consume memory/resources when they shouldn't. Just look at Android for an example of this.

Windows Phone is actually very good at managing stuff even if you leave apps running, I've never had a problem when I have left them running, but by default I close them as force of habit.

Windows RT, I know that if I have a ton of apps open on my Surface RT it will drastically slow down, so Microsoft do have some work to do in this regard.

As you say badly written code is probably responsible for tombstoned apps still wriggling. I tend to close everything down after each extended session of usage where I have been doing several things.