i let them live if they impress me, most i kill. also depends how quickly they move - a fast spider is hard to transport found a dysdera in my closet while spring cleaning, it was so striking i had to let it live so i could see more of them. i googled it after to learn what type of spider in my area looked that way and if it was venomous- only then did i get to see its fangs! if i knew how epic this spider was i would have kept it as a pet.