The legendary Nexus 5 had the unfortunate issue of a faulty power button that would stick in its slot, depressing the mechanical power switch on the phone's motherboard, causing a boot loop.
With the iFixit tools, I was able to carefully disassemble the device, remove the motherboard, and completely eliminate the power button from the equation. After some charging, the device powered up and booted flawlessly.
Always opt for the most tools you can afford. Ever the deal-seeker, I contemplated purchasing a less comprehensive kit from iFixit, but opted for the Pro Tech Toolkit. During repair time, I wound up using more tools that I thought I would have to, and am glad I had a full suite to choose from.