Excluding the whole issue of "junk", okay?
Consider the life of a valve spring in an automobile engine. Just for drill, figure 2,000 rpm is 1,000 spring-cycles a minute; 60,000 times an hour. And I've got some 270,000 miles on my Toyota. Saying 40mph average, just for the heck of it, that's some 6,500 hours.
Anyhow, is that enough cycles to suit anybody?
Why should decent-quality magazine springs "just lie down" on you?
, Art