I'm an aspiring crafter, but after getting my gatherers to 50+ I made it a point not to hold onto mats. I know how nice it is to have mats on hand, but the stress of inventory management just isn't worth it. More retainers = more management, so I currently have no additional retainers and acquire/craft mats as I need them. The only reason why I want additional retainers is to increase my ability to acquire mats, not really hold on to them.

Some mats, especially regents and other cross mats I will mass gather/produce HQ and hang on to them, but even these are thrown in the company chest after I am done for everyone to use. I'm hoping I can keep this up throughout the leveling process using the two retainers I currently have. I still need to level the classes I want to assign to additional retainers.