Anon, I'm so sorry but your mantis friend isn't gonna last very long. :c
If you want a long-term segmented friend, try a tarantula. Those fuckers last a long time if you treat 'em right. Mine got to be around 20yrs old, and supposedly they can live longer.
I've read it depends on the species. "New World" species tend to be docile with harmless or low-toxicity venoms with urticating hair as a defense (hair that can come loose and irritate your skin, giving you itchy skin). "Old World" tarantulas tend to be more venomous with aggression as a defense.
Also, "New World" tarantulas are usually fuzzy, "Old World" tarantulas usually aren't.