Originally Posted by
ZephyrMenodora
I think in general, while time can be a factor, it is difficulty that is the core determinant. Casual content excludes difficulty past a certain level - but casuals can be fine meandering at their own pace on easy content and long-goals that they can work towards over months/years of logging in randomly if they are so inclined. Casual content doesn't expect a lot from the player in regards to skill levels or extensive game knowledge.
Of course, you could view someone as hardcore who is online 24/7 but only does basic casual content. But I'd just view such person as a casual player with a lot of free time lol.