They all pretty much said it. You’ll get way more than you need to fill it. I am not even halfway through, i am about 3/4 of the way through it. Of course, this is my 2nd run through the game(i took a hiatus earlier to close my FF11 account to play some WOW).
This time, i am focusing more on using technicks, and so far, it’s payed off. It’s hard to figure out which technik is best for which situation. Some monsters a technic will do hundreds of damage to, others, almost none. But it’s cool, because most are AoE(area of effect) technics, and they don’t cost MP. (I know, i know, i have alternate spellings for ‘technik’, i forget how it’s spelled so i figure to cover the field, LOL).
You could always try to specialize, and make your characters very specific with the license they learn, but ultimately, that is unrealistic, and will lead to really weak circumstantial characters that you can’t switch out in the middle of a battle. I found it’s better to have everyone learn everything, and then customize job through the gambits.