We tend to see the same group of about 20 friends on a rotational basis. Some every 2 weeks, some once a year. I don't think there is any hard and fast rule
One thing I have learned living in Montagu. Social norms are far more open and forthcoming than in Cape Town. People just seem easier to get on and reciprocate more readily. When you drive past someone you know, you slow down and greet them, not put your foot down and give a passing wave