Weekends don't factor into my life since I am on a rotation so wasting a Sunday or any other day doesn't factor in... and my travel days counts as work days, from the moment I step out of my front door to when I return. I don't oftern go into work on arrival and they do make sure I have a hotel room to go to even if I don't check in until 7am.
I use the money earned during travels to upgrade when I can, which is why BA's AUPs are so useful when they arise, especially on the flights going back to UK. It's a shame the POUGs on BA don't work for me due to TA and third party flights in the booking.