Here's a breakdown of considerations:
Eevee:
* Early Evolution: Evolving Eevee into a starter stage (Flareon, Jolteon, Vaporeon) early on offers a strong type advantage for the early game. They have powerful moves and good stats, making them strong team members for taking down early bosses.
* Late Evolution: You can choose to keep Eevee as your primary attacker and evolve it later into Umbreon or Espeon for better late-game utility. Umbreon has high defense and access to status moves, while Espeon has high Special Attack and Psychic moves.
Pikachu:
* Early Evolution: Pikachu can evolve into Raichu early on for a powerful Electric-type attacker. This is a solid option for players who want to utilize strong Electric moves early.
* Late Evolution: There is no other evolution for Pikachu in this game, making it a good choice for players who want to keep Pikachu as their primary attacker throughout the game.
General Considerations:
* Type Advantages: Consider what types are most effective against the enemies you're facing. Early on, Fire, Water, and Electric types are strong against many common opponents. Later on, you may need different types like Psychic, Dark, or Ghost.
* Move Pool: Analyze the move pool of each evolution and decide which moves are most beneficial to your team strategy.
* Personal Preference: Ultimately, the best time to evolve your Pokémon is when you feel it's the most beneficial for your current gameplay and team composition.
Remember:
* You can only evolve Eevee once in this game.
* You can evolve Pikachu into Raichu at level 30.
* You can obtain evolution stones to evolve Eevee into Flareon, Jolteon, and Vaporeon later in the game.
Don't be afraid to experiment and see what works best for your playstyle. Have fun exploring the Mystery Dungeon!