keeping leftovers

Other day i was checking out my fridge. i was suprised to see the number of leftouts in my place. I usually throw out leftouts which are longer then oneday.
Today after seeing the number i was in dilema whether to throw them or keep them. I started searching in Internet. Most of them were saying that it is safe for weeks. But i was wondering whether they are true or not.
Here are the facts which are told by Mary Weaver, with retail food safety for NSF International, about leftovers.
http://www.wtopnews.com/?nid=106&sid=913740&sidelines=1


Left overs are common in everyones house. We always feel it is safe to reheat the leftover food and have it. but did you ever thought how long can it be safe.
we trust our eyes and nose most of the time when it comes to leftovers but did you ever realise that eyes and nose are the determining factors which decide food posioning.