Crappy Smartphone

My first smartphone was a Samsung Vibrant (aka Galaxy S9000) and it worked well for several years. About two years ago, I replaced it with a HTC One M8. At the time, conventional wisdom was to get a Samsung Galaxy S4 or an Apple iPhone 5; I got the HTC to show some love for Taiwan. I also ended up buying a special case (dot view) and an external camera (HTC Re) for it.

Last weekend, I noticed that the phone was cracked along the edges, and the glass screen had a bulge in it. Most likely the internal battery went bad since the phone wasn't holding much charge either. Lithium ion batteries tend to heat up and swell as they deteriorate. I'm kinda pissed since the phone cost me $650 and only lasted <2 years, while several iPhone 4's and my OG Galaxy is still fine. The HTC phone still works but now I'm afraid it will catch fire or something when the battery finally dies. Debating whether to buy a battery replacement kit online (looks like it will take hours to open case and replace battery), or get a new (expensive) phone. Sigh...