I don’t have a lot of experience with bearing buddies, but, I’ve found that once they’ve been installed and you remove them the interference fit is reduced when re installing so much so that I’ve lost one and found another loose. Now when I remove them I replace them with new ones.
Unless the wheel bearing is loose, there is a grease seal leak, or they were run with too little grease allowing the piston to bottom out and not keep positive internal grease pressure when submerging the trailer and water intrusion is suspected there is really no need to remove them.
As the instructions say below, when first using them, keep checking them / adding grease as the air pockets work their way out of the hub cavity and the piston collapses. When adding grease to the bearing buddy don’t add so much that there is no room left for the piston to move outward, the spring is fully compressed, when the grease expands when it gets hot. There is a built in pressure relief that will allow excess grease / pressure to escape but it makes a big mess under the dust cap.
www.bearingbuddy.com
When I make a long trip to go boating I will check the pistons as the directions say by pushing on one side of the piston before launching my boat just to make sure the piston is sitting on grease.
These are far superior to EZ lube axles in that EZ lube axles do not keep positive internal pressure on the grease to keep water out.