If you've ever eaten questionable leftovers after they've been in the fridge for a long time and never gotten sick you need to be thanking God. For those of us who risked it quite a number of times and had leftovers that had been at the back of the fridge for days, maybe even weeks, didn't have a happy ending.
And the reason why this keeps happening is because most of us don't really know the specific number of days we should have leftovers in the fridge before consuming or throwing it out. The basic test is to try and remember how long it's been in there, then smell it if there are any funny odors.