Always a good idea to check it. Never know when a download will screw up. Especially if you download it on mobile network or iffy wifi. If you don't check and something screws up, it's your fault. I have had corrupt roms flash but not boot before, so it's not guaranteed not to flash.
If you are flashing anything that has to do with firmware, for the love of God check md5 EVERY TIME. Bad bootloader or radio flash and you are SOL FOREVER.
You can check MD5 in es file manager. Hold press file. Properties. Check sum.
I have a checker in my computer as well. Just a free one I found.
Sent from my ADR6425LVW