You have a lot of misconceptions about bearings.
1. They do not dry up. What happens is they heat up and the grease deteriorates from the roller surfaces.
2. You repack to force OUT the old worn grease and push in NEW grease
3. You need to repack bearings once a year.
4. Unless you have the new style Dexter bearing lube system, injecting grease thru an EZ lube does not adequately get to the roller bearing surfaces. You NEED to get rid of the old grease.
5. Inspecting (pulling) once a year and repacking is GOOD insurance from failure miles from home. Doug