I think he means a change in routine caused by them simply not enjoying the work anymore, so they come late or leave early or take long breaks etc. And yes of

I think he means a change in routine caused by them simply not enjoying the work anymore, so they come late or leave early or take long breaks etc. And yes of course digging for signs doesn't beat asking by far. Ideally performance reviews can fill this role (sadly, at least here, too often those are treated as just a legal obligation where the only practical goal is to discuss and most importantly document some complaint, no matter how small, so that just in case the company later decides to fire the employee, they already have a file with "evidence" that you were underperforming for a long time).