How much work do you need in the marketplace to make a viable income?

I've created a formula that works for me. Obviously its not cast in stone and will vary depending on the popularity of the artist, but I work with an average return factor of 10% of the consigned value of the work. So for instance if you have R100,000 rands worth of consigned work in the marketplace, I'd expect an average monthly return of R10,000. In summer that'll rise to 20-30% but decrease to maybe only 5% in the winter months. This formula excludes special exhibitions etc. Point is if you have R100,000 worth of work in galleries its unlikely that you'll be erning R50,000 a month. Seems obvious but many artists are afraid to have too much consigned work - they want everything to sell as its completed. If you want a R50,000 average monthly gross income and your work sells price to artist for say R5,000, then in order to achieve R50,000, you'll need R5000,000's worth of art in galleries which translates to 100 paintings. Try it and see if it works for you.