I have been using a root feeder on my trees for 10 years now.  I have a large yard with over 30 trees and I feed the trees 4 times a year.  So, my root feeder gets a lot of workout.  My previous root feeder came apart last year (again - after 10 years of usage) and I bought the same type of feeder again without hesitation.  Feeding trees via the roots makes my trees about the best trees in the neighborhood so I know the product works.  And since it lasted this long I feel I got my money's worth.