I've had poor results from success mechnaics. It's awful when your dice are cold and you end up doing nothing. At least as a warrior you can keep swinging your sword.
For the most part I prefer daily recharge / rest. I really enjoyed playing RuneQuest (II) back in the day, and I liked their spell mechanics. There was the Power attribute, rolled similarly as Strength, Intelligence, &c. If your character had a Power of 12, they could cast 12 points of spells "per day". Spells (Battle Magic) ranged from 1-4 points, although some were fixed at a certain value. Coming up on a tough fight, cast Bladesharp (3) on your axe for a bonus to hit and damage. Power goes from 12 to 9.
The interesting thing is that Power did not refresh completely after a night's rest, but rather 1/24th of the total after an hour. It didn't matter what you were doing as long as it wasn't some extended magical working or other exception. In the above case after 6 hours those three points of Power would be restored, regardless of whether they were sleeping, hiding, exploring, or boating down the Zola Fel.
For casters, it would be interesting to have them regain a level of spell power per hour, maybe.