Tank gear from 30-60?

[Iscah]

Something to be careful with below Lv50 is that the "recommended gear" button is often very unhelpful and will give you higher-level but lower-defence gear that isn't meant to be worn by tanks, because they can also equip DPS gear (marked for all DoW) and mage gear (all classes), so make sure it isn't doing that to you.

If you want to use the recommendations, move all non-tank gear out of your armoury chest and double-check the stats of any "upgrades" it suggests for you.

Definitely buy poetics gear at Lv50 - at least your weapon and body gear, more if you can. Pick up an encrypted tomestone and some carbontwine from WoD if you can.
(But also check the marketboard for prices on anything better than the i90 gear you'll get from the Lv50 quest.)

[Niwashi]

Something to be careful with below Lv50 is that the "recommended gear" button is often very unhelpful and will give you higher-level but lower-defence gear that isn't meant to be worn by tanks, because they can also equip DPS gear (marked for all DoW) and mage gear (all classes), so make sure it isn't doing that to you.

The recommended gear feature looks at actual stats, not levels. Or rather, level is at or near the bottom of its priority list. I think the only time it chooses by level is when two pieces have identical stats but different levels, which can sometimes happen with a lower level HQ item and higher level NQ item. (It's not even limited to the stats an item starts with, as it can shift an item's relative value when you add materia, so it's not just looking it up in a fixed list.)

That's not to say it always makes the best choices. It seems to have a hierarchy of stat priorities and stops as soon as it finds a difference. It will favor even a single extra point of your main stat over any number of points of defense (which is the part that can make it seriously wrong for tanks sometimes) and even a single point of defense over any number of good damage boosting tertiary stats (which can sometimes be a poor choice for a damage dealer).

As to removing non-tank gear from your armory chest when leveling a tank, there are a few levels where the BiS gear for tanks is gear designed for LNC/DRG, and at least in early levels you might occasionally even have regular DoW gear that's better than your tank gear if you've gotten one of the better dungeon drops for DoW but have only regular NQ tank gear (especially if that tank gear is from a few levels earlier). I'd say it's better to just double check the recommendations. They're a good starting point, but if you know you have something better, equip it instead.

[Iscah]

That's not to say it always makes the best choices. It seems to have a hierarchy of stat priorities and stops as soon as it finds a difference. It will favor even a single extra point of your main stat over any number of points of defense (which is the part that can make it seriously wrong for tanks sometimes) and even a single point of defense over any number of good damage boosting tertiary stats (which can sometimes be a poor choice for a damage dealer).

To be exact, I'm told it's based on the Vitality stat for tanks - except that stat also gets added to a lot of gear for other classes as well, so it might as well correspond to level in that case.

And yes, rather than take everything out of your armoury chest at the beginning, take it out piece by piece if the recommender tries to give it to you (and you're not needing it for another class).

I do consider "tank-and-lancer" gear to be tank gear though.