What actually happens with the ground coffee that lost its flavour? Ground coffee looses quickly its flavour. It's especially painful for singles living in rented apartment (no coffee machine) and having only big packages in nearby groceries...

But what actually happens to that coffee? What is lost, other then flavour? How the taste is affected? Does the caffeine amount also changes? Do some chemical processes happen, that can make such an old coffee unhealthy?
As far as I know the aroma is gone first, the oils begin to dry out and the taste goes down as well. I don't know how long it takes the caffeine to go away. I have drunk coffee over a year old and there still was caffeine. (I go camping and there was a bag left over from the previous year.)

On a different note - as a lifelong NYer I don't see how living in a small space precludes having a grinder. Even - gasp - a cheap krup kitchen grinder is better than buying bags of store ground coffee. (IMHO) Although I would buy a hand grinder instead.