Maxxing in 1 Battle: The True Grind

[FFIX Choco Boy]

So Saturday is my bonus day. I woke up yesterday with 2 lvl 100s, and went to bed with 14... How is this? Trust me, it wasn't because I had nothing to do yesterday, but rather that I found an awesome exploit.

If you have the 2x exp boost for your bonus day, a way to get to 5x exp with your chocobo, a few EXP boosting accessories, the Magic Pot manual summon, and a way to verse a lvl 100 ExDeath, then you can actually max a character from 1 to 100 in 1 battle.

Set ED to lvl 100, cautious behavior, average strength, equip all the exp boosting stuff, and on bonus day when you get the 5x multiplier, verse him. Let him break you so he gets 9999 bravery, then wait to regen, and use Magic Pot. Then, hit him with an HP attack, you can get a lot of exp from this, because of the 10x from the chocobo/bonus day, then extra from accessories(I had 2 eggs, a wing, a feather, and the other one, for a total of 51.84X normal exp) as well as the extra from him being 99 lvls higher, and hit 100 right away. I got somewhere around 4.1 mil exp from the 1 hit. So, hope this helps you get your lvl 100s.

If you plan on doing it with more then 1, then be sure to quit the game after you beat him and the Rematch option come up, so you preserve your 5x exp multiplier w/ the chocobo.

[Wolf Kanno]

The infamous ExDeath trick...

I tried a minor version of it to level some of the villains but in the end, I decided not to. It doesn't help leveling skills and several of your characters early skills are awesome once you master them and get the branching attack with it. My other issue with quick leveling is that it doesn't help you with learning the characters and I find from time to time that its harder to use high level abilities with a character if you didn't learn the basics.

Its a great trick if you have no plans on using the character (I may need it for Tidus) but I feel its better to grow with the character if you intend on using them as a main. ;)

[FFIX Choco Boy]

It's mostly for getting the stupid achievement.

[Barraza]

The infamous ExDeath trick...

I tried a minor version of it to level some of the villains but in the end, I decided not to. It doesn't help leveling skills and several of your characters early skills are awesome once you master them and get the branching attack with it. My other issue with quick leveling is that it doesn't help you with learning the characters and I find from time to time that its harder to use high level abilities with a character if you didn't learn the basics.
This.

Ability-mastering and equipment (primarily accessories) are way, way more important than leveling up; I can easily take on a character twenty levels higher than I am if I am properly equipped and have good abilities.

I don't see it as cheating, but it really hurts yourself in the long run. Also, have fun fighting to pick up all the AP you would have gradually picked up if you didn't cheat.

Besides, the normal way to reach level 100 is actually pretty quick, all things considered.