Although I'd be able to do my job without them, my quality of life has dramatically improved thanks to browser extensions.
With them, I can:
- Block 99% of ads (popups, banners, YT ads, etc). I can also use this extension's picker to block elements of my choosing (e.g. an annoying sales banner)
- Create custom CSS themes and override any webpage. For instance, if I know I'll be looking at a lot of documentation I'll set up a theme that turns the background dark and the text white.
- See what technologies (languages, frameworks, reverse proxies, etc) a website is using.
- Block access to a URL between X and Y hours a day, certain days a week.
In terms of products, I used to use Evernote and used their desktop app for a brief time, and it was nice because it synced with the browser extension. However, I almost never used the app and used the extension 96% of the time.