The phone runs stock ICS and had been working fine for months, but one day it began going really slow.
For example, when using the messaging app, he clicks send and there's an animation moving the text to the thread. It now takes a few seconds after the animation for the text to appear in the thread.
Another example, exiting the messaging app takes sometimes 20 seconds.
Another example, it takes more than 10 seconds for the gallery to appear. He claims it was always lightning quick to open.
I've seen it reboot by itself. He says it crashes like that often.
I worked with him to backup all his pictures etc, then did a factory reset. His new strategy was to only install a few apps (facebook, business calendar) but the phone has again started presenting the same symptoms, in exactly the same stock apps.
I've suggested it's a hardware issue and that he should take it into the shop. Is there something I'm missing in diagnosis, or is my recommendation right?