Even the "natural/necessary" distinction is ultimately nothing more than a rule of thumb and we don't have any significant examples of the Epicureans dwelling on it as as bright line test. ...
THAT category helps to protect us from runaway, innumerable, limitless desires that run to infinity, and this is a crucial component of Epicureanism. If there is no satiation, if you're in a constant state of anxiety and of craving needless things, you won't be able to abide in pleasure. Diogenes on his wall includes limitless desires as one of the roots of all evils. So it IS kind of important to know that we don't need much and that what we need, we can easily procure. Everything over that is the cherry on top.