I've read unlocking your phone is good prevention from bricking.

[mycophiles]

I also hear it's extremely hard to brick your phone.

Do you guys keep your phones unlocked or do you lock them after you update?

Just asking.

[neodorian]

You just need to unlock them to flash a custom ROM. If you want to flash one of the official ROMs you need to run the re-locker. "Bricking" your phone (i.e. making it permanently unusable) is incredibly rare. Unless you do something weird, you can just reflash it if you screw something up.