If you verbally agreed to allow them to stay until the last day of August, why is he leaving September 1, 2008?
Are they paying a premium for these extra couple of weeks?
IMO 24 hours notice is sufficient for something like this especially when it appears to have been an on going project. However, I think work done in an occupied unit should be schedule between 8:00AM & 4:00PM or 9:00AM & 5:00PM. It appears as though your painter would be there until at least 6:30PM.
I guess you will learn at least 2 things from this.
1. Verbal agreements aren't worth much
2. No good deed goes unpunished. --72.85.xxx.xx