Mario Golf: Super Rush allows players to use their own Mii character and golf alongside iconic franchise characters like Mario, Luigi, and Peach. While these Miis may not be as recognizable as other characters in the game, they do have the added benefit of being able to level up and gain stat points. Depending on how players spend these stat points, their Mii will become a better golfer and specialize in certain attributes. That said, there is a limit to how much players can upgrade their Miis, as they will eventually hit the maximum level and stop earning stat points as a result.
In total, there are five different stats for players to level up in Mario Golf: Super Rush: Power, Speed, Stamina, Control, and Spin. As players level up certain stats, others will decrease as a result, and these points cannot be respecced or changed. Because of this (and the fact that there are a limited number of points available), it's important to make smart decisions while leveling.
The max level in Mario Golf: Super Rush is level 100. After reaching this point, players will no longer be able to gain or spend stat points to increase their Mii's stats. As previously mentioned, there is no way to respec these points, so players are stuck with whatever stats they have by the time they reach level 100. The only way to change this stat spread is to create an entirely new Mii and level all the way back up to 100, building the stats out differently the second time around.
Since Miis start at level 1, they will gain a total of 99 stat points on their way to level 100. Putting all stat points into the Power stat will cause the player's maximum range to be 360 yards, but will decrease their speed quite a bit. Keep in mind that Power is the only stat with no cap, and all of the other ones will eventually max out. For example, Stamina caps out at 150, while Speed, Control, and Spin all have a maximum value of 10.
It's generally believed that Power and Control are the most important stats for Mii golfers, as these stats won't ever decrease and the others aren't required for the Mario Golf: Super Rush's story mode. That said, players that plan on using their Mii for things outside of the story mode should be sure to invest in stats that they feel are most useful.
Mario Golf: Super Rush is available now on Switch.