So what are the largest costs of running such a business? Well to be honest, that is time. Time I could have spent with my wife, my brother, my dog, instead of answering support emails from my first waking moment to right before sleeping. Time I could have walked outside, do some handy work in natural light, instead of sit on my butt and wreck my spine 6-12h a day. But time is hard to quantify, so let’s talk about money instead.
Source: Costs of running a macOS app studio business — Alin Panaitiu