Over time, people discover that some things are just better off left to the experts. These are the people who have the knowledge and the proper tools to do the job quickly, easily, and better than you could do it yourself.
In many instances, one has to look at the time factor involved. If it takes you, say, three hours to do all the domestic window cleaning in your home, then perhaps you can hire someone else to do the job and pay them with the money you earn from doing two hours working at your own job.
Instead of “saving” money by doing it yourself, you actually end up saving money by hiring the job out and concentrating on your own specialized way of earning a living. That’s how an economy works– by having people perform their own specialty and hiring others to do theirs.