Actaully latent effect means that you must meet a special requirement for the effect to happen. for example with wizard earings you must have BLM as your sub job
While wearing it, open up your magic skill menu. Your elemental skill is listed. Take the earring off, and check it again. You'll be able to see the difference if it is working--which it will, if you have BLM subbed.
my god there are only 5k posts about these latent items...some latent effect items take effect when HP are in the yellow... all the lvl 30 latent gear,is dependent only ON THE SUB JOB..if you have the right sub you get the effect, if you do not have the correct sub, you will not recieve the effect regardless of where your HPs are @...