What's a map allowance?

[Naberrie]

Leveling other jobs can be useful, aside from cross class skills. For instance, if you level MNK or LNC you'll find that positioning is very important for those jobs. As a tank, you'll then understand how important it can be for you to position mobs and hold them steady in such a way to maximize the damage from LNC and MNK if they're in your PT.

[NotTheNameIWanted]

For PLD you will probably want to get Conjurer up to 34 eventually for Stoneskin

Is that for soloing? Because in groups the healer should be keeping that up on me, right?

[Sagittarian]

For PLD you will probably want to get Conjurer up to 34 eventually for Stoneskin

Is that for soloing? Because in groups the healer should be keeping that up on me, right?

If you have a WHM generally yes. Their stoneskin gives 18% instead of 10%. I think the Stoneskin SCH have is only 10% also, so it's a toss up there.
It can also be useful in certain situations where the healers are otherwise occupied keeping everyone, well, healed. With the second boss in Qarn, for example, he just starts ignoring the tank and picks another party member to wail on as a part of his attack rotation. I take the opportunity to cast a few stoneskins to help keep everyone up. There are also a few fights in Crystal Tower where the healers are constantly busy so popping the occasional stoneskin as off-tank can help.
Edit: It's also fun for when you are running lower level dungeons and the healer is level-synced below where they get stoneskin - you can still have it equipped as a cross-class skill. I get amused by using it in Sastasha and Toto-Rak.