When should I start worrying about gear?

[AnimaAnimus]

Update your gear as you get gear from each level of dungeons, starting from lv15.

Horrible advice. You walk into a lvl 15 dungeon in lvl 1 gear I am out, idc how good you claim you are. You should always keep your gear upgraded. If nothing else it makes dungeons, fates and hunting log kills all the much faster. And the gear is so cheap and can so often be used cross-class there is no reason not to keep it up to date.