Question: what level does eevee evolve into espeon in crystal?
Answer: For Espeon, I think if you evolve it before Level 36, you should be fine (unless you want the move Swift; then you'll want to have it evolved by level 30). That's what the Psychic Pokemon learns Psybeam; if you miss that, you'll have to wait until it learns Psychic before you get a Psychic move.