To be tridoshic means that you have an equal balance of vata, pitta and kapha doshas in your constitution. A tridoshic person can be variable, dependent on how the doshas blend with one another. The personality is generally even and steady because by nature, the constitutional forces balance one another out. In other words, it is more difficult for a tridoshic person to go out of balance. The general protocol for tridoshic-types is to follow Ayurvedic lifestyle practices according to the given season & environment. Since there is an even balance of all five elements, tridoshic skin is generally more healthy and balanced than other doshic skin types.
Tridoshic-type skin also has an equal balance of all 5 elements: ether, air, fire water and earth. Therefore, people of tridoshic nature have an equal proportion of vata, pitta & kapha. Due to this equally balanced constitution, it is harder for tridoshic skin to experience imbalance.