In Path of Exile, if there's one resource people who play a lot but easy to ignore, the answer is time. Whatever else you can put up some PoE Currency for trade, there are 24 hours in a day that you get to make use of stuff, including playing the game. Many of these players who are serious about the game don't think about it as much as others, as they've dedicated their time and energy into playing the game, but they also have to sleep and do daily life things.
Therefore, it is crucial to be able to experience as much of the game in as short of a time as possible. That includes farming and grinding PoE Items very quickly, that's quite an important part of the game. Being able to clear areas in the game that make out the most amount of experience and poe items are not too difficult, the major part of that process is the builds and skills that go into doing what you want to do.