I have a heat issue with my recent iPhone 5S purchase. I have a Gold colored one and it loses battery quick while emitting some decent amount of heat with minimal app usage. Running GPS? Drains my battery like crazy with good signal and a lot of heat. I also have a warm phone from calls or internet usage as well. Is it time for it to be replaced by Apple? I also have signal issues, which causes a drain, but I use Wi-Fi/Airplane Mode combos to save the battery normally if I have Wi-Fi access.