See me once, I'm the first of my kind
See me twice, unhealthy lives we left behind
See me once, because there's only one
See me twice, then there's something we shun
See me once, some mistake me for a mountaintop
See me thrice, without me many devices flop
Here are the previous riddles in this series (the solutions there have nothing to do with this one, only the process of getting there).
#1, #2, #3, #4, #5, #6, #7, #8