When I first started doing electrical work I took some romex and abused the
hell out of it; bending it sharply back and forth dozens of times, hammering
staples in way way too tight, etc. I then cut it all apart and found it was
all fine.

While I don't recommend treating it roughly, it is very durable stuff.

(on the other hand, a mouse chewed through a piece and nearly burnt my house
down; go figure)