It is important, in my belief, to focus on one business at a time. It is efficient and responsible. It helps to achieve more.
I often ask myself, “Do I do the best I can do for maximising my outcomes, growth and happiness by doing useful and good activities?” And I am very happy to answer “Yes”.
It is essential to ask and answer such question because the life is short and there is the limited number of cycles in life: there is the limited number of working weeks, working months, opportunities to create/change/finish projects and so on. It is important to focus on one business, I believe, and it is also really crucial what that business is.