Typically, rotator cuffs(shoulder joints0, like knee joints and wrist joints and ankle joints, tend to get “overused” quickly, we use them everyday in our every day activites and we used them all the time in our sport specific activites, so when we decide to strength train them it is best to keep the reps low, not high.
Most people will get should complications, just as the get knee complications from overuse and too much “time under load”.
The thing is, especially with the shoulders, too much weight can be very dangerous.
You need to find that sweet medium that allows you to strength the shoulder and NOT do more than 10 reps, perferably in the 6-8 range.
Also, try to avoid lateral raises and upright rowing as the tend to be the major causes if “wear and tear”.
Also be careful on doing flies for your chest, they put the shoulder under lots of stress.
Doing 5X5 ( for example) of overhead presses = only 25 reps, whereas doing 5 sets of 12 = 60 and well, typically build far less strength.