when to get upgraded loot chests?

[~Sound Sage~]

So there are several parts in the beginning of the game where people say to leave some chests alone and to loot them later on in the game for something better.

is there a guide on this? can you tell me what chests i should save for later, where they are, and when to loot them?

right now im at the point where i just recruited mog at the narsh mines

[Puzzlemint]

Narshe Mines (3 chests), Figaro Cave (3 chests), and South Figaro (~10 hidden items) are the only locations with upgrading chests, and honestly none of them are really worth waiting for, but if you want to go for it, you can grab them any time after getting the second airship.

The items in South Figaro change from consumables you'll probably never use into consumables you'll definitely never use

The chests in the Narshe Mines are:

Phoenix Down (actually useful in the first half of the game) -> Guard Bracelet (fine, but there are better accessories)

Sleeping Bag (again, actually useful at the beginning) -> Elixir (you probably already have a dozen of these)

Rune Blade (reasonably good weapon when you get it) -> Ribbon (you probably already have one or two of these, and it's only useful for uncursing the Paladin Shield)

The chests in Figaro Cave are different, since there's two points where they upgrade, the first being Locke's solo scenario, and the second being the midway point of the game. Their contents are:

Ether (meh) -> Thunder Rod (probably the only one actually worth getting, since it lets you one-shot the Tunnel Armor) -> Hero's Ring (Admittedly one of the best accessories in the game, but you should already have two or three of them, and there aren't that many characters who benefit from both bonuses; everyone else is fine with just Earring or Gigas Glove)

Ether (meh) -> Still Ether (still meh) -> Hi-Ether (ehhh)

Phoenix Down (Again, actually useful early on) -> X-Potion (Honestly less useful than a Phoenix Down) -> X-Potion (Still less useful than a Phoenix Down)