Health question.. rotator cuff?

I've damaged both shoulders about 3 years apart, and about 15 years ago, in unrelated falls. They will never be the same. I have to be very careful, especially in the early morning, reaching above or lifting above. Sudden jerks are killer. Sometimes just arguing with my belt around my backside, a jerk, and it hurts. One of the things I can NOT do anymore, is argue with those damn little tweeky gas powered weed trimmers. The tiny recoils and the "snap" when/ if they fire and start just instantly devastates my shoulder.