in what fashion would like heroes to learn skills/abilities

In an RPG, how would you like your hero to learn abilities and skills?

Would you have the normal learn new ability as you level?
Or would you learn abilities by buying ability spheres and other items?

A mix would be cool, have the standard abliltys that would come with the unit, say a paladin, of course he would have heal and some type of aura. But if he wanted a ability that only a different class has, he would need to buy a ability sphere, or if he wanted a special ability, no one has he could buy it.

Or even better, he could buy perminant (in the respect that they couldnt be "used up") spheres but only use them when he got to a certain level. That would offer a neat way of customizing your hero.

By completing side quests, etc they could then have the option to learn(buy) an ability sphere from whoever he helped.

thxalot. this really helped

spheres sound really FFX-2 ish, u sure this isn't a final fantasy map?

i guess i might have been inspired by the ff series to make this rpg.

I dont need to necesiarily use spheres. i could use boots that give the windwalk ability. I've never played ffx-2 so i dont know how they did it.