I only have one Z-Wave lock and one hub. I added 4 Aeotec repeaters: One by the hub, one by the lock, and the other two in between. My lock has been steady and responsive with no issues.
I think it was in a lock-specific thread in here someplace where it was suggested that one of the repeaters should be close to the hub. There also seems to be a consensus that the Aeotec repeaters are more effective than wall warts.
