When leveling up a certain Job becomes unimportant...

[Peter_20]

Lots of Jobs in Final Fantasy 5 offer many great, and bad, Abilities.
Some of them are worth getting, and some others are negligible.
Let me give you an example: the Knight.
This Job starts off with some decent Abilities, Cover and !Guard, which are somewhat useful for, say, the Monk.
However, the real great Ability from this Job is no doubt the Double Grip, which increases your attack power by x2.
After that Ability, the Job isn't interesting anymore.
From then it just gives you those annoying EqpX Abilities, and you can easily skip the Knight for a Sorcerer with the Double Grip or something.

This goes for lots of other Jobs, and some of those are just temporarily uninteresting, e.g. the Wizards; they won't reach LV5 White and Black until (SPOILER)the second world and therefore there's no real reason in leveling them any higher in (SPOILER)the first world.
Same goes for the Monk as with the Knight: the last three Abilities are just HP+X%, working upwards,
and are not very useful at all.

[ThroneofDravaris]

Since you get stat bonuses (and sometimes abilities) for the bare class by mastering other classes, there isn’t really a point at which there is no point in leveling them up…

[Shin Gouken]

mastering a theif is boring and unrewarding, but the final theif ability "footwork" which gives a character theif speed, becomes a default ability on your bare class. same for blue magic "learning" ninja skill "2-swords" and lots of others. i agree to a certain extent, after learning a knights double grip ability i generally lose the knight class for something else id rather have, like the sorcera as you suggested.

[Peter_20]

mastering a theif is boring and unrewarding, but the final theif ability "footwork" which gives a character theif speed, becomes a default ability on your bare class. same for blue magic "learning" ninja skill "2-swords" and lots of others.

That's a good reason to master all Jobs, although I was talking about the Action and Support Abilites, not really the rewards for the Bare Job.

I LOVE Bares during the end of the game, they're totally crazy; they execute just about ANY Support Ability in the whole game - except for the Berserk Ability, of course.

Gotta love using all those Support Abilities for free:

Cover
Brawl
Counter
Passages
Dash
Caution
Footwork
Learning
Barrier
Pre-Emptive
Two-Swords
DmgFloor
AntiTrap
SwordGrab
Medicine

Not only that, but you can use ANY equipment and have two Action Abilities.
You also get all those boosts from certain Jobs' stats, like higher Strength, Agility and Magic Power.

Bares =

[eestlinc]

of course then there is the hunter or red mage, who are not very good at all until you get x-magic and x-fight.

[Shin Gouken]

of course then there is the hunter or red mage, who are not very good at all until you get x-magic and x-fight.

reds are useful as soon as you start the game as they can use black and white magic up to level 3 as default. hunter is much easier to master but isnt really all that useful unless you learn sorcera, 2-swords, doublegrip or time magic. combining x-fight/sshot with any of those abilities is devestating. im a physical fighter person