After that I see them flake out to the point I put them in the recycle bin.
Try one thing. Do a full reset of the phone as some apps blow up when there is no network.
I just got a Galaxy S5 to replace my S2. I still us the S2 for some functions. It now goes on and off by itself, initially taking about two minutes to boot up when I first turn it on. Making clink sounds every 30 seconds - for about five minutes. This phone has lasted all this time and is still good. What's the deal with it acting like this?