[DoingIsLearning]

Arguably these contracts are a legacy of factory shifts in industrial revolution times.

What (most) managers want is your output, irrespective of how long it will take, may be 12h or 3h.

One could argue, that while working 3h or 4h one should still be available to support, help, communicate, meet with, your team and stakeholders for the remaining hours of that contract.

I would not have an issue with less hours provided you don't ghost for the remaining hours, if one of your colleagues hits a block, or your manager gets hit with a shitstorm, then you need to have a communication line open (which should also not be 24 hours but for the hours in your contract).

[naavis]

This I agree with. But I would say being available to help and support and whatever is part of the job. If you say you work for 4 hours, but still have to be available for all of the above for 8 hours, you are working for 8 hours, not 4.

[andirk]

In "agile" or "scrum" or whatever story pointing is, the "level of effort" is often touted and rightfully so. The mind can quickly become exhausted after grueling mental labor. Personally, I often get some 5 hours of solid work in one day and consider that enough. Other times, I'll work 10+ hours in a day on less mentally grueling work but I rarely bill over 8 hours in one day even if it's more. I always want my employer to see the cost of me as well worth it.