If booking early, make sure you also check the rate available if you book direct through the hotel (try the hotels website).
If you have good travel insurance, you can book early direct through hotels websites and often will be entitled to significant discounts (at least in Europe I've found that to be the case).
Usually these discounted rates are non-refundable and require the entire amount to be prepaid...so if no show, no refund and the entire amount is lost...hence the need for good travel insurance.
Sometimes though if booking early and staying for a few days, the hotel might have a 'long stay' offer available only to direct bookings (though sometimes made available to booking websites too).
Last year I spent 2 months in Europe and booked ALL my hotels bar one direct and 6 months in advance, using non-ref rate discounts where available. Worked out MUCH cheaper than using a booking website, and I reckon I ended up with better rooms as well due to booking direct (apparently thats a myth, but on my experience I'm not so sure). For instance, I often put a request to have a room with a balcony...most of the case, my request was met.
This year doing the exact same thing, 2 months in Czech, Turkey and Greek Islands mid Aug-Mid Oct. About to start searching for hotels now.
Cdchi1