I usually ignore Pokemon like Aipom or Murkrow unless they're under 200 CP since they have really low catch rates and don't evolve (meaning theyre only worth stardust).
High level Natu and Paras I will often ignore if I'm not swimming in Pokeballs, since their catch rates aren't extremely high. Eevees I tend to go for since they evolve quick and are very useful, but, like starters, Eevees have low catch rates, and are, to me, often worth a great ball and razz berry if they're mid to high CP.