I would start by using them on every set and repetition. Use a weight that is controlable. Focus on a controlled concentric action, and use a slow 5-count eccentric portion. This should decrease the number of sets and reps that you have to perform, but causing more damage(good thing).
If you have a partner, you can load up the machine or bar, have them help you with the concentric action, and make you do all of the eccentric work.
I would need a list of what lifts you do and what type of equipment you have to be of better assistance