If you are thinking about performing routine maintenance on your Mac, or any other computer regardless of the operating system, then I can already tell you that you are making the right decision. Computers are in severe need of proper maintenance on devices, and it is best if you take care of your device without any issues whatsoever.
Now when it comes to maintenance from the software side of things, you have two options. You can either start going through everything you have, and clear things on your own. This takes time, but gives you a more granular control over how you will be cleaning. Other than that, you can use a software to do the job. If you are on Mac, then Mackeeper is a great option. But do not take my word for it, and go read the mackeeper reviews.
Below are a few things that are better to consider before going ahead with the maintenance.
Software or Manually
Whether you are going to do it using a software as I have talked before, or you are going to do manually. The latter offers much better control over things, however, it takes longer than usual to get the job done. So, make sure that you consider this possibility beforehand.
Hiring a Professional
If you think you lack the proper experience or time, then I would suggest that you consider hiring the professional. This makes things a lot simpler because when you do go to a professional, they will not only do a software maintenance, but if the need arises, they will also do hardware maintenance. Which, of course, is much better, and will restore your machine to its original glory.