Just thought I'd help you out

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1. The Nexus 5 doesn't have carrier bloatware. Rooting affects 0 stock apps.
2. Could be a very valid point. But if you remain completely stock and just root (no system modifications) it should update just fine.
3. Nexus devices are almost impossible to brick. I promise you not, you could try to brick it and it's recoverable. As long as your EFS partition remains intact - which it should since you, the user can't touch it with a ten foot pole, the phone is nearly 100% ***** proof - Android Central is very sensitive to language for it to block out ***** proof

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4. You can always unroot and relock before sending it back. If it can't boot they won't tell anyways. Plus I'm pretty sure Google's pretty lenient with rooting and warranty since it is a developer/Nexus device.
5. Not sure what you mean. I do know the device value can go up because it's rooted...
Hope I was helpful

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