It depends on the time of year.
At the times when the sheep need to be more closely shepherded ie pre lambing, tupping etc they are on the lower ground and are looked at at least once a day, sometimes twice.
At other times when there are fewer things to go wrong, they are away on the mountain and one or other of us will walk round every other day. Having said that, we might walk round and only see a small percentage of the sheep that are up there.