This common question depends primarily on the answer to one question. Why did you get hurt in the first place?
If you accidentally tripped and dislocated your shoulder in a fall (i.e a one-off accident of external causation) then the usual injury and rehab time is about 12 weeks. If however the answer to the question is along the lines of, my training had been going pretty well but I developed a niggle somehow, and then all of a sudden my hamstring popped. The answer for the hamstring tear is also about 12 weeks, but by the sound of it, this injury was caused by an internal event (a weakness or imbalance within your body). In these cases, the actual rehab time could be a whole lot longer. The majority of weaknesses and imbalances that we see have taken a lifetime to put there, and that means that you could be looking at months of dedicated hard work in order to undo the bad habits of that lifetime.
Is it worth the effort? Well to ensure that you live to be healthy and happy in old age, we would definitely say so.