It annoys me to NO end, just look at all these who evolve late:
Vanilite -> Level 37: Vanilish -> Level 47: Vanilluxe
Deino -> Level 50: Zweilous -> Level 64: Hydreigon
Rufflet/Vullaby -> Level 54: Braviary/Mandibuzz
Larvesta -> Level 59: Volcanora
Mienfoo -> Level 50: Mienshao
Sandile -> Level 39: Krokorok -> Level 40: Krookodile
Scraggy -> Level 39: Scrafty
Tirtouga/Archen -> Level 37: Carracosta/Archeops
Gothorita/Duosion -> Level 41: Gothitelle/Reuniclus
Foongus -> Level 39: Amoongus
Frillish -> Level 40: Jellicent
Ferroseed -> Level 40: Ferrothorn
Klink -> Level 38: Klang -> Level 49: Klinklang
Tynamo -> Level 38: Eelektrik
Elgym -> Level 42: Beheeyem
Litwick -> Level 41: Lampent
Axew -> Level 38: Fraxure -> Level 48: Haxorus
Golett -> Level 43: Golurk
Pawniard -> Level 52: Bisharp
They're all in the high 30's to early 60's range. That would be fine, though the forms should be more spread out. For lines with 3 Pokémon in it, they should evolve in the teens or 20's, not in the high 30's and then again in the late 40's. That's too bunched out and IMO it should be more spread out.