It's all about the Balance
When I were a lad...1 (It is in fact more than half a lifetime ago.)
My first permanent & pensionable job included the work hours defined as Thirty seven and a half hours per week taking one week with another. 2 What was extra in one week could be balanced out the week after. A couple of hours this week for an external reason could be made up next week.
My then manager took me aside after a couple of months and explained, that if the job didn't broadly fit the hours defined in the contract then one of two things was wrong.
Either the role (including tasks and time) was badly defined.
Or the employee's approach to the role and the work as wrong 3
Figure out which it is and address it
Has stuck with me since - to the extent that when work mobiles became common place I'd power down the phone shortly after getting home. Out of hours was not categorically ruled out - but it is the exception not the rule and it involves a quid pro quo.
1Takes brief diversion for Monty Python sketch....
2Those of a certain age and/or background may recognise the phrase
3Including the possibility that they just didn't have the requisite skills