How to unlock the Nexus 5 bootloader

It's easier to unlock your Nexus 5 bootloader than it is to decide if you want to do it

If you're receiving your shiny new Nexus 5 in the near future, you'll want to think about unlocking the boot loader. It's a bigger undertaking than the folks on the Internet make it out to be, and doing it later is a huge pain in the kiester, so it's worth talking about.
First things first. Since it's a Nexus device, it was designed to be easily unlocked. There is no extra encryption layer, no signing your life and warranty away at the website of the people who made your phone, and no software hacks to try to bust your way around things. You only need the SDK and be able to use the command line — which are things you need to know about before you ever decide to unlock your phone anyway.
The how is even easier. Turn on USB debugging on your Nexus, plug it in to a computer with a working SDK, and type the following commands:

• adb reboot-bootloader
• fastboot oem unlock

Then follow the instructions on your phone's screen. Really. That's it. It will erase everything on your phone, so it's a good idea to do this right away if you ever plan on using it.
But before you do it, remember a couple things. Unlocking your boot loader makes your phone unsafe. Period. It just does. Think of how easy it is to unlock things. It's equally easy to get all your personal data off of the phone, even with a secure lock screen. Your boot loader is unlocked. The phone will flash any files it is told to flash — including ones used to root and suck everything out of it. There's also the warranty to think about, though Google has been more lenient on that than other OEMS — they say it "may" void your warranty, not it "will" void it. And finally, if you want to use the Nexus in any BYOD plan at work, check with your IT guys and make sure it's OK to do it. They like stuff to be as safe and secure as it can be.
In the end, it can be rewarding and is a crapload of fun, as long as you understand the risks.