I have arthritis and degenerative joint problems; part of which affects my right shoulder to the point I can't use free weights anymore and this Xertube Resistance Band fills the bill.  I use it for my P.T. routines as well as general resistance exercises.  They don't last forever; but they do last a long time and do a great job.  The door accessory works well to let you do cable routines just like on the cable machine in the gym (one of my favorites) .  Tones and strengthens without undo stress on the joints.