> there is no limit where one can say, "My work is done"

I'm a couple years into my first software job, at Google. We don't do performance evaluations relative to whether you're doing as much work as you're capable of in 40 hours. You're evaluated against a fixed rubric corresponding to the job level. In other words, if you're capable of doing a Software Engineer N's worth of work in 40 hours and your title is Software Engineer N-1, you can either put in the 40 hours and get promoted to Software Engineer N eventually, or you can work less and still be perfectly productive relative to your current role's expectations. Plenty of people make that latter choice and work well under 40 hours.

I don't know about Google, but Facebook and I presume some other big companies has an up or out policy. If you come in at Software Engineer N, they expect you to get promoted to SE N+1 in X years, and if you don't, they'll start evaluating you at that level anyway, and assuming you continue to put in level N work, you'll get a performance improvement plan, and then probably fired. There's some level which is considered ok to be 'terminal', you can be promoted above it, but they're also ok with you sitting at that level forever.

Just trying to say be sure to sniff around and make sure you understand the actual expectations.

At Facebook the first terminal level is L5. At Google it is L4.

This is my impression at where I work as well. If you work at a company like this you can effectively already work 4 (or less) days a week. If you currently work at a company that you feel tracks your time then if you do somehow “win” a 4 day work week you’ll probably still be expected to put in 40 hours OR take a 20% pay cut. Either way it doesn’t seem like being told you now only work 4 days a week is materially changing anything.

Also you have some days where you feel super productive and get loads done and some where things are difficult or you are tired and not a lot gets done. If you leave early on the productive days, would you stay back longer on the days you aren't doing so well?

And how do you know if you were actually very productive one day and not that the task was overestimated and actually very easy? Would you want to be on the hook for underestimated tasks? For me its easier to just say "I tried my best for x hours" and leave at the same time every day except in times of urgency.

> If you leave early on the productive days, would you stay back longer on the days you aren't doing so well?

No, I do exactly the opposite. I work longer when I'm super productive, and I cut out early when I'm not having a good day. It seems obvious that you'd try to optimize for working the hours when you are most effective.

> And how do you know if you were actually very productive one day and not that the task was overestimated and actually very easy?

I think that comes with experience - sometimes you just know when the ideas are flowing and the code seems to write itself, and then other times you recognize that you've spent hours banging your head against something only to realise you overlooked something trivial.

But why? What benefit do you get from giving your best days to the company and not use them for yourself? Usually you don’t get anything in exchange for working hard.

Sometimes I have days where I'm just really focused on work problems.

Sometimes I have days where I'm killing it in the gym or on the track.

Sometimes I have days where I just want to work on my garden, or sit and read, or spend 4 hours on an awesome dinner.

I assume most people have rhythms or cycles like this.

Thankfully I have a job that doesn't measure daily output, but instead looks at productivity over a longer period of time, so I can work towards a life where I'm always doing the thing I'm best at, at that moment.

A day where the work I've been doing just comes together like magic isn't transferable to a personal project.

> Usually you don’t get anything in exchange for working hard.

A nice paycheck at the end of the month?

But pay does not depend on how hard you actually work.

Sure it does. My employer notices when I work hard. Since they want to retain me as an employee, they compensate me accordingly. Similarly, I were to _not_ work hard my employer would certainly notice and want to reduce my compensation.

Working hard is not the same thing as working long hours or giving extra of myself. Working hard simply means working intelligently, thoughtfully, and to the best of my abilities.

We have tasks assigned for a two week period. If I finish roughly as many of my tasks as my coworkers finish of theirs I count it as "My work is done".