I'm sure everyone has lacked focus and attention to detail every now and then. Most of it is due to habits unrelated to the graphic design profession such as lack of sleep, lack of interest, or too many...
In any business hourly rate can make it or break it
Do you find presenting your hourly rate to a client can put your client in judgmental state, cause all they see is $$ signs and think
they can get it cheaper somewhere else? Now all they think is so many hours = $$$$
This is after the cost of the project scope was given and more work was required and charged by the hour.