One other thing to add, just like you can change classes by switching your equipment, you can change jobs too. Once you get access to them, there are very few reasons not to have a job stone equipped on your DoM/W classes. About the only time you see people without them are people who somehow missed the fact that they exist, or in some specific cases people will go without for PvP. The only downside to a job crystal is that it restricts your cross-class skills a little versus the base class, but this is made up for by the more specialized skills related to your class that the job crystal gives you access to instead.