I think that unfortunately, the answer to this question is: it depends!<p>My $0.02 is that it depends really on the market size (based on your startups focus) and its growth. If you are early to a space then trying to grow your startup full-time will burn you out, and similarly if it is a large market that is not growing much you might need to work on it with a team full-time and put in a lot of effort to get market share.<p>My bias is to keep it on the side until you have a certain amount of product/market understanding. Doing that and having enough insights about your industry can take time once you start playing in it. Once that happens, and if you can make it happen, do a pivot as needed and double down.