A trainer can receive an amount of Experience Points to gain a level in Pokémon GO, marking their progress. To level up, the trainer must catch a certain amount of Pokémon to receive Experience Points, XP. Each time the trainer levels up, the XP scale is set back to 0. Leveling up allows the trainer to obtain and unlock better items. Any amount of XP can be doubled by using a Lucky Egg. The trainer can receive an XP from certain actions. These are: