Shouldn't make any difference. I do a physical job and have to give equal service at the end of the day as at the start. Same for them.
Saying that though, one time I saw the always excellent Sienna (GFE Bury) last thing in the evening. She looked tired and I could tell she was struggling to keep up. She was a trooper though and gave it her all, never complained. When I'd shot my load she just collapsed on the bed. Later admitted how tired she was but I found it endearing more than anything.
