As somone who has worked in freelance world for a long long time, I can vouch for the time management. I lived through some horrible times, and even in those days I always calculated what I had left in my time to certain periods and tried to work. Many nights of working at coffee shops, many early days at starbucks, many hard working periods at hospital cafe, all thanks to having some time management.
Its still quite hard, because it gives you the chance to not work if you do not want to, its freelance work so if you work then you earn but if you don't work then you don't earn and that gives people some devilish thoughts of "I already spent so much time on other things and got tired, I do not want to work today" and sometimes I lose to it, but usually I do gather myself quickly.
Time is the currency you ar eselling, everyone can write, code, design, whatever you do, its matter of learning and everyone can learn it, I am not some smart mastermind and say nobody else can do it, everyone in the world can do what I do, its just about learning how to do it, and that requires time, and then requires people to spend time doing it after they learned how to, and that is time too. So you are selling your time, and thats why its so important.