If you can afford 10 hours playtime or more everyweek, u have the initial conditions to buy it
If you could spend 10hours straight or more on raids or camps, you definitely
could buy it and I can see your potential as a hardcore.
If you like grouping, you could buy it.
However, it could become quite addicted like Tobbin said. So if you have something like a girlfriend that require lots of maintenance, you might not want to buy it.
Finally, I did play Everquest. I had a 54 wizard on prexus, but I deleted him a while ago, and canceled my account