Pulling the drums allows you to inspect the brakes as well as the bearings. I, earlier this year, performed my annual service on the bearings and, not expecting any issues, found one of the four brake assemblies failed, shown in the photo below.
When our rig was only six months old, I used the zerks to grease the bearings, following the instructions in the Dexter manual to the letter,
https://www.dexteraxle.com/docs/defa....pdf?sfvrsn=42.
Six months later I decided to pull the drum/hub assemblies and found three of the four with grease covered brake shoes. $500 later for new backing plate brake assemblies and cost to have the drums turned, the rig was ready for travel. I have never used the zerk fittings since to grease the bearings. A couple of years ago I had a Dexter installed bearing fail, and a short time later I upgraded the bearings to USA Timkens. Keystone does not do anything with the bearings on these rigs as the axles are fully assembled by Dexter and then the complete axles are installed on the frame.
We had the drum brakes on this rig upgraded to discs while at the Western Region Rally at Coos Bay, OR, so drum brakes are not going to be an issue for us anymore. I also paid extra to have Timken bearings installed with the discs instead of the Chinese bearings that would have been installed.