To Me if Providing is the only source of income there's no such thing as low volume the hobby is how she supports herself. But if some has a part or full time job what would actually be considered once or twice a week, four times a month just depends. As stated above with "KK" one can be more selective.
If this is a lady's full time job, then I would say 2-3 gents a day would be low volumer for her. It really just depends on what's going on in each individual lady's life. Mosr really low volume ladies see 1-4 men a week, but they usually have a job, go to school, etc and find this to be a relaxing hobby that just happens to pay well.
I fall in the latter category but it doesn't mean that I am in any way better than ladies who see more gents than I do, or worse than ladies who see less. If a lady can see upwards of 5 guys a day and be refreshed, happy and full of energy for each one, in my mind she has really nailed the perception of being low volume and is a much more skilled provider than myself because I couldn't do that with that amount of people, I would burn out.