How much time do you spend on the "fourth characters"?

[Peter_20]

Alright, we all know that Frioniel, Maria and Guy carry around some guest characters during most of the game, and since they are no permanent characters, there's usually no real reason to spend time on them, as they will leave soon anyway.
It does help a lot with some characters, though; I usually find myself spending lots of time with Layla, because she stays for a very long time.
Here's how much time I spend on each character:

MINH:
NOTHING, because he already rules too much in all possible aspects

JOSEF:
I have him learn Cure and Fire, and I have him cast magics until he's got about 25 MP; this is very helpful in the Ice Cave

GORDON:
I seldom spend much time with him, but sometimes I feel extra ambitious and bring him a Flame Spear from Mysidia - I also have him learn Cure and Ice, but only because I have those spells in the item menu, and I want to get rid of them XD

LAYLA:
this is the one I develop the most: she's very useful against sea-enemies, so I level up her Bolt spell a few levels; I also give her any weapon Frioniel doesn't use anymore, and eventually she's a VERY good fighter, especially with the Orihalcon knife, which rocks

RICHARD:
I leave him the way he is, BUT I immediately give him a spear; he's a Dragoon, ffs, why the heck is he using swords?
I don't care if he sucks with spears in the beginning, he does develop very fast in the Mysidia Tower (about 4 levels)

That's my two cents; you can use my tactics, or you can give me advice on how to improve it.
But I especially want to hear YOUR strategies, so I can learn from you as well.

START RESPONDING!

[Captain Maxx Power]

I used to not spend any time of any of the characters with the exception of Leon later on in the game. However in the GBA version I spend quite a bit of time levelling up both Minwu and Richard for obvious reasons. I also make sure Richard is packing Osmose and Drain before he cops it.

[Sefie1999AD]

Minh: I might level up his MP a bit. I usually have him cast defensive spells when I'm leveling up by fighting the monsters NW of Phin, so some of his spells might gain a level. Otherwise, he doesn't really need leveling up.

Josef: I have him use his fists and train with them for a while. I may teach him a spell or two.

Gordon: I usually level him up a bit until he gets a bit of MP for casting spells and enough HP to survive. Gordon is actually a pretty good character after you've leveled him up for a while. I usually have him fight with a spear, though I often give him a few basic spells too.

Layla: I usually give her the basic spells and have her develop the Bolt spell since that one starts on a higher level. She's mostly a fighter, though.

Richard: He's my tank. I may give him a few spells, but mostly it's his attack and defence that shine, while everything else about him isn't really that great. He's got a lot of HP, he doesn't take much damage and he hits for a lot of damage.

Lionheart: I know you shouldn't do this, but he's a bit like a red mage character. He has some of the basic spells, and I level up some of them, such as Cure, Life and Holy. Otherwise, he's a left-handed sword fighter with a shield. He seems to develop very quickly.

[Zeromus_X]

Besides Lionheart, I never really bother to level any of them up.

As for how I build them, I normally leave them more or less default:

Ming-Wu: I steal his staves to sell them for quick cash. I let him cast his spells, but he's already powerful enough so I don't normally bother leveling up any of his attributes.

Joseph: He just hits things. He doesn't stay long.

Gordon: I give him dual spears.

Leila: I give her daggers and level up her Thunder magic.

Richard: Two spears, if I recall, you find some nice spears for the duration of his stay.

Lionheart: This varies. Usually I'll give him spears or swords, or even axes. I may also give him some helpful magic like Cure and such.

[DarkLadyNyara]

I use them normally, but I don't make an effort to level them.

[Crossblades]

I dedicate no time whatsoever in developing the 4th characters. The only thing I do is raise their HP

[Peter_20]

Lionheart: This varies. Usually I'll give him spears or swords, or even axes. I may also give him some helpful magic like Cure and such.

Giving him magics is a good idea, I'm sure, but I'm hellbent on giving all chars certain "jobs".
I don't even want Gus and Leon to gain any MP, because they are fighters, and giving them MP or anything magic-related feels strange.
I even restart the game from the beginning if any of them even gain one extra MP, which tells a lot about how nerdy I am. XD

[Bart's Friend Milhouse]

Richard?

[rubah]

The guy with the really big nose

[Cid Vicious]

His name is Ricard people, not Richard.

The only one I spend any time on is Layla, but only because you get her at a tricky part of the game. So I need her help. The rest I don't bother too much about.