Baldy, It is good that you have already had the procedure done. With the rotator cuff, the longer you wait, the more difficult it is to fix it and after a certain amount of time, it can't be fixed.
How long it takes to get back to 50 or 75 or 100 percent depends on what the doctor had to do. Did he repair a slap tear, did you have a frayed cuff, a torn cuff, or was it more of a cleanout? Was it a complete tear or was it a partial tear or did they have to staple it back to the bone? What damage was repaired will give you a time table of anywhere from 8 months to 15 months to get back to being as good as it will ever be. What was done also will determine whether it will ever be 100 percent of what it was before the injury or not.
The most important thing you can do is to make sure you do the rehab just like you are told and do the complete program. It will be immobilized for a while and then they will start to move it and stretch it and break down the adhesions. The first couple of weeks are very painful and the breaking down the adhesions are very painful. However, if you do not do the complete rehab correctly, it might get slowly better for a couple of years, but it will never be as good as it could be and will take alot longer than if did the rehab. It is very important that you are patient and you do not reinjure it by trying to do too much too quickly, this would almost for sure cause permanent damage.
Many people find that after the rehab program is finished, their shoulder is better than it ever was before surgery, unless it was injured so severely that it couldnt be completely repaired.
Good luck and hope it recovers a complete 100 percent