It does depend on the engineer, their team, their location, etc, but I can describe my work day.
8:45am – Arrive at the campus, head to gym for an hour of training, shower
9:55am – Grab some breakfast before it all gets cleared off, eat
10:30am – head up to my workstation, log in, start going through emails.
10:30am to 12:30pm – work, with breaks to get more coffee and water
12:30pm to 1:15pm – lunch
1:15pm to 6:00pm – work, broken up by coffee, meetings, occasionally by presentations or TGIF(T)
6:00pm – head home (eating dinner with my wife, not at work)
I’m a Xoogler. I was not the happiest Googler, so I spent very little time trying to accomplish one last thing before departing for home when I should have left two hours ago, and the work was just… something I had to do between things I enjoyed doing. Had I loved my work and team more, I would undoubtedly have spent more time doing work, and described the work in detail here… I did at my previous job, for ten years, and I am again at my current job… but, as I said, these things depend on the engineer, the team, and the location.
The upshot? Google has terrific benefits and opportunities, but no matter what, to be a great engineer, you need to enjoy your work. When I enjoy my work (like now), my day goes more like:
1. Wake up (no alarm) and start thinking about that problem I’ve been mulling over since last week…
2. Shower, make breakfast, play with possible solutions in my head…
3. Drive to work, trying not to be distracted by that elegant solution I just came up with…
4. Get to work, check for important emails, leave the rest for later (or ignore them)
5. Meet with some other engineers to work on the design of our project.
6. Take a break, read some of the less urgent email; maybe check Quora or some other internet activity.
7. Start implementing that elegant solution…
… oh, crap, lunchtime’s almost over!
8. Grab lunch to go, hurry back to my desk
9. Test my solution, fix some minor issues, and find someone to show it to.
10. Get some reviews on my code and tests.
11. Take a break for exercise. (I skip this one far too frequently. I need to work on that.)
12. Tackle another problem from my backlog, or maybe something new that I just came up with, if the backlog isn’t too urgent…
13. Force myself to leave, because I love my wife even more than my work… and I’m getting hungry, and there’s something I promised I’d make for dinner…
14. Make dinner, eat, maybe watch some television with my wife.
15. Think about what I’m working on while I’m cleaning up after dinner.
16. Bedtime. Eventually, sleep.
Source: Quora Post by Nathan F Yospe