The idea of having multiple jobs is scary for some people and they just can't seem to get past the idea to get to the benefits. If one job pays you $30 per hour to come in and be committed to that one job for forty hours per week and you are content with that good for you! However if there were four jobs that you would do simultaneously that each job paid you $10 per hour and you could work from anywhere that you could conveniently and simultaneously work all four jobs for forty hours, you would make $40 per hour which would be a $10 per hour increase for no extra hours. There would be more actual work involved but no additional hours. While this may not be the best scenario you get the idea. While working multiple hourly positions may be more difficult to do simultaneously a pay by the job type position would be very doable! 

This could very much depend on the industry you are in as well as your education and background. There are many options to take on extra projects in any field. The idea is quite simple there are always more money options. If you keep your doors open to those options you will make more income. The key is to never close a door to opportunity. As long as the doors are open, the opportunity can come right in and earn more income. Whether that particular opportunity lasts forever or goes away take advantage of it for a minute and find a replacement once it's gone! 

Many people do choose to get paid by the job instead of by the hour. There is a reason for that. The money is better! There are other options than working day in and day out for the hourly wage. Some people just can't get past that idea. Once you do the doors begin to open and many others follow! What you choose to do with them is completely up to you!