There are two kinds of devs— those who are completely oblivious of their UI setup(themes, fonts, IDE layout and so on.) and just use their editor or IDE out of the box and then there’s the other kind, those who spend hours tweaking anything that can be tweaked and get their hands on. I’m definitely the latter. Which side are you, and how much have you customised it?
EDIT: I did not mean beautification, I’m asking along the lines of productivity too. For example, using a high-contrast theme to aid your vision, rather than use the light theme that comes as default.
Many extensions too provide automation of mundane tasks, such as auto-close tag, etc. This speeds up your workflow, no?