My Tech:
Droid Turbo 2 64GB on Verizon
MacBook Pro 2010 - 8GB RAM, 500GB SSD, 2.3Ghz Processor, 13"Retina Display Custom
HP EliteBook 2760p - 8GB RAM, 250GB Hard Drive, 15" touch/stylus based screen
HP Revolve 810 - 12GB RAM, 1TB SSD, 13¨ Touch screen
Droid Razr M - 8GB
Nikon D3200 - 24.3MP, 1080p video recording
HP Chromebook 11 Gen 3
Don´t bother ordering a battery from anywhere other than iFixit. Their batteries are actually OEM parts and they include a warranty for 1 Year (most batteries from other places, like amazon, typically have 30, 90, 180 day warranties. After installing, make sure to FULLY charge the computer (don´t use it during the first charge!) to make sure your battery life is prolonged to its fullest lifespan.
Removing the battery is not required, but in some instances can make installing ram much easier. If you plan on upgrading from 4GB (2X 2GB) to 8GB (2X 4GB) Removing the battery would be better. There are two levels of ram. If you are replacing both levels, then remove the battery. If you are just replacing the top, dont bother. Removing the battery for very long or even at all (depending on the CMOS battery age and health) could possibly reset settings, the clock, saved wifi passwords, and more.
Do this step slowly! Depending on the age of the components, both ram and the system board, removing and inserting RAM can actually break threads on the board that read and write info to the ram sticks. It should be very easy to remove the ram. If it seems hard to remove, stop and make sure you have followed all the steps correctly!