I have been waiting for a theoretical engineer type to tell us that a spring sitting in a compressed state,,,valve open,,,,undergoes any more stress than operating at 1000's, millions of opens and closings over a period of time,,,,just wondering. Like a bolt torqued to say a 100 pounds for 10 years,,,will the bolt stretch any amount that after 10 years, would it would show any less torque than initial torque reading.