2 - 5 Minuten
My problem was getting blurry pictures when I use my iPhone's camera. The reason was that the camera's external cover was scratched a lot. So, I Had to replace the whole rear panel.
The whole replacement process did not take more than 2 minutes. The new part matches the previous one. I had no trouble at all, and the new part looks exactly the same.
Just get the right tools from iFix it, and then get the exact part you need. don't be afraid to fix your stuff by yourself..