We're considering switching from 10-4 to 11-4. The only thing stopping me is the fact that if we do that, I have a sneaking feeling that the late check out requests won't slow down so what's the point?
Thoughts?

I use 11 to 4. My house keeper needs every bit of this time to clean a 3/2 house.

I don't get many late checkout request. The only time I allow it is when I don't have a same day check-in.  

I usually offer an early check in or late checkout when the schedule allows it.

One guy checked out 45 min late and my housekeeper sat close to the end of the drive way (she's too nice to pull up to the house), but the guy saw her and must have felt bad and gave her a $20 tip.

I dis buy a super capacity washer and dryer since the laundry is the bottle neck in getting the house ready. I do have extra sheets, but she always just does all the laundry and remakes the beds while she cleans the house.

I do 10 to 2 and try to accommodate late check-in/check-out requests when possible (but it's rare).  There have been a few times that I have suggested to a guest to just book another night at lower rate if they request this prior to booking.  Recently a number of guests have just stayed late, up to an hour, so I implemented a change to my house rules to charge them for every 15 minutes they stay past their check out time.  Seems to have stopped this behavior.  My cleaners usually show up right around 10AM and are done in 2 - 2/12 hours.  

I also use 11-4, which gives the housekeeper plenty of time. I set my door codes to actually work an hour prior to check-in and an hour post check-out. That way, they don't get stuck if they leave just a few minutes late, or call me thinking the code is incorrect if they show up 5 minutes early. Then, if I get a request for early/late I tell them they have an extra hour, but that's all we can do.