If it breaks, it might still be under warranty. Many can be fixed.I bought mine used several years ago. It's probably at least 10 years old by the looks of it. I don't think they really need to be replaced often unless you want a different style, or it breaks.
Let me guess -- is it a Hot Shot?My release is over 30 years old and still working great. The only that needed to be replaced was the rope but otherwise no problems at all. You can't beat a high quality product.