Well....ok. I will have to say I am probly the most interested in this "thread"....ar ar ar.
I use primarily internally bonded polyester thread in tex 90 size, by the 1 lb spool (4,200 yards per). Go thru probly 2 per month. Thassa lotta threads
(shit's not cheap for the good stuff either).
Kevlar is used in high-heat applications, ie, firesuits etc and costs twice as much. My spools are about $30 per and that shit is $60.