About a month ago, I'd say, I started having very infrequent complete lock-ups. I'd pick up the phone and try to turn on the screen and nada. It would still be running as the notification LED would sometimes pulse according to my Lightflow settings. Plugging it into my computer, it appeared as an unrecognized device and adb wouldn't be able to get anything from it. I've never had this happen while I was actively using the phone, mind.
Holding down the power button until it force shuts down and rebooting it works just fine, but it's a bit annoying and worrying to have it go blank every few days. Once, it was even completely working but the touchscreen would not respond regardless of what I tried.
I since did a factory reset, thinking it might've been a kernel issue (I was running on faux's kernel) and it went fine for a week but it just did it again... And this is on stock 4.4.2, rooted, without any new app in a long time (ie. I can't think of an app that I'd have installed when the crashing started).
Any ideas, short of writing it off as the occasional problem and planning on a much earlier replacement than initially expected?