We often calculate in linear ways whether we have time for something or not. Exercising takes 3 hours a week and I have no three hours of dead time, so it can’t happen. Same with the hobby that you love but that is unfortunately not as important as all the other demands on your time. The problem with this logic is that we pretend that everything exists in separate little boxes, which if added up make 24 hours a day.
However in reality it’s rather like a stone that you throw into a pond. Each action influences each other action. If three hours of exercise, more sleep or more fun influences almost everything else you do, you might suddenly find that you actually have more time, because your previously tired or lethargic brain does stuff more quickly. Or you stumble upon business opportunities while doing something fun which might have taken you weeks of cold-calling and emailling.