For some GLA/MRD/LNC gear, the gear is intended for lancers and dragoons. For others, they're intended for tanks and lancers/dragoons are kindly allowed to wear it. Check the Mdef. If it's lower than Def, it's lancer/dragoon gear. If they're the same, it's tank gear (mainly applies to the level 23, 32, 38 and 46 scale mails).

With shields, some shields are gld/cnj/thm, or gld/thm. Check the stats on the shield. If they're str/parry-related, they're gladiator/paladin shields. If it's int/mind-related, it's for them magic users.


Related to the first, it annoyed me so badly back when I was still trying to get my Infantry set completed from Brayflox normal, when the tanks would just not roll on the pink scale mail pieces, despite wearing level 20-25 gear (or worse, DoW gear). Their excuse? "It's not tank gear D:" or "I have gear of that level already" (DoW gear). I headdesked so many times.