We recently had a glass company come to our house to repair a broken window. Since our house is over 70 years old the repairman had to make quite a mess to remove the old, original pane – scraping away layers of whatever they used to hold window panes in 70 years ago. Chunks of that whatever were scattered across our floor.
As I would expect from a professional, he swept up the mess before he left.
In digital work it is much harder to see the mess. Useless commented out, poorly formatted, or uncalled code. CSS that doesn’t do anything or is repeated unnecessarily. Irregular naming conventions. These are the same kind of mess as the window scrapings that were on the floor of our house.
A professional cleans that up. Even though the customer or client will never see it. Even though it takes extra time that you might not have.
You are not an amateur – it’s part of the job.