Usually an iphone 4s repair company will look at your iphone 4s and see what’s wrong with it. They’ll make sure to look at the entire phone and measure out the entire thing so that they can see if there are any differences or something on the inside that they would need to change. There are times when somebody can drop it just a bit too much, and for every single time that they drop it, the phone becomes broken on the inside. When this happens, you’ll find the phone to be lacking or lose some of its main speed because of the fact that you dropped it. Basically, a good iphone 4s repair service will make sure that each aspect is fixed and repaired when you get the phone given back to you. Remember that it all depends on the services and the company itself, so look for a company who is legit and real.