You can try this website: Yellow Gremlin (link in text).

If you scroll over "Databases," then "Items," you can click on "Gear" for particular body parts, "Weapons" for particular jobs, or "Tools" for particular jobs, and it will list all the Gear, Weapons, or Tools, and the optimal rank for each. Checking on that stuff is a good way to keep track of when the next potential upgrade will be available.

For Gear, be sure to check what types of jobs it favors. If you're using armor that does not favor your job, then you'll get substantially less benefit from the gear.

Good luck!