its a how long is a piece of string question really mate, if you have the work then you put in the hours that the work requires, if you don'y then you can have shorter days.
also depends on how much travelling time is involved in your daily work schedule, 2 of my rounds are 15-20 miles away in either direction so I finish later than I would if if working close to home.
for instance on wed/thur next week I do my biggest monthly contract ( 2 day job ) they wont let me start until after 9am as its a large privat country estate and I have to be off the grounds by 4pm, work all day the 1st day and usually finished by lunch time the 2nd day so I usually book some other work in for the afternooon.
also have some weekend commercial work