Finally got my tube bender up and going last night , and as i was trying it out on some 1" tube I started wondering how do you tell when a die has worn out. do they ever wear out? surely the pressure die will some day even with proper greasing. so how long should i expect my die sets to live and what is the first sign of trouble? both my 1" and 2" dies are new, i am just wondering for down the road.