I have used an Otterbox Defender case on all of my iPhones since day one and wouldn't think of using anything else to protect my phone. However, I have noticed with all of the cases that after a year or so the rubber or silicone outer shell seems to get slightly larger and softer to the point where they don't properly fit the hard plastic inner shell anymore. My wife's phones have had a similar problem over the years and her problem appears even sooner than mine. I am guessing that the shell absorbs skin oils or lotions used on the hands and the result over time is the softening and enlarging of the outer shell. I found a cure on the internet that worked for me. Simply put about 2 inches of water in a sauce pan big enough to allow the soft shell to lie flat on the bottom, add two or three drops of liquid dish washing soap and bring the mixture to a rolling boil then drop in the soft outer shell and remove the pan from the stove and allow it to sit for 3-5 minutes. When time's up remove the shell with tongs and rinse in cold water, dry it thoroughly and put it back on the phone. In my instance the case was indeed fitting tighter on the hard plastic shell and seemed to get even better over the next 12 hours or so.