Level up

Level Up is a term often referred to in RPG games. A character must defeat enough enemies in battle to gain enough experience points to level up. As the character grows to higher levels, more experience points are needed to level up. Once the character levels up, their stats are increased and he may also learn a new special skill or attack. Additionally, all stats are fully recovered in a level up.

Super Mario RPG: Legend of the Seven Stars
Upon leveling up in this game, Mario or one of his allies can chose one of three stat combinations to get a bonus on along with the regular stat boost. The three choices are attack and defense, represented by a hammer; max HP, represented by a Mushroom; and magic attack and magic defense, represented by a star. At certain levels, the characters will learn a new special magic ability. The maximum level is 30.

Paper Mario and Paper Mario: The Thousand-Year Door
In both of these games, Mario must choose one of his stats to boost. If he chooses HP or FP, his maximum for that stat increase by five points. If he chooses BP, his maximum BP will increase by three points. The two other stats remain unchanged.

In Paper Mario, Mario can level up his partners with a Super Block. These blocks are spread throughout the Mushroom Kingdom. Using one allows Mario to upgrade a single of his party members to Super Rank. After he has received the Ultra Stone from Raphael the Raven, he can use the same blocks to upgrade partners to Ultra Rank. Super Blocks turn useless after being used once. The maximum level Mario can reach is 27.

In Paper Mario: The Thousand-Year Door, the player can level up Mario's Partners by giving Merlon Three Shine Sprites. Then the player selects one partner to level up. One level up will give Mario's Partners the Super Rank. To level up the partners again, Mario must first obtain the Up Arrow. After doing so Merlon can level them up to the Ultra Rank. The maximum level Mario can reach is 99.

In Paper Mario, the music played when you level up is a remix from Super Mario Bros. 3's overworld theme from World-1

Super Paper Mario
In this game, level up bonuses are preset, alternating between an increase of five HP at every even-numbered level and one attack point at every odd-numbered level. Note that all party members in this game share the same stats, excluding Bowser, whose attack power is always doubled. As is the case with The Thousand-Year Door, the maximum level the party can reach is 99.

Unlike in other games, Mario's party can also permanently increase their HP and attack power without leveling up by using the HP Plus and Power Plus items. However, both of these items are very rare.

Mario & Luigi series
In these games, max HP, max BP (Superstar Saga only), max SP (Bowser's Inside Story only) Power, Defense, Speed, and Stache are all initially increased, generally anywhere from zero to five points, but as high as fourteen in Partners in Time, immediately after leveling up. Mario and Luigi can then choose any stat they want and give additional points to it. If a stat receives too many additional bonus points in a row, then the number of additional points given to that stat is reduced. A roulette determines how many additional points are added: up to five in Superstar Saga, up to six in Partners in Time, and up to seven in Bowser's Inside Story.