I want to book a reservation at a Marriott resort using points. I know I have to book far in advance in order to use the points because they only let so many rooms go to point users. I don't want to pay extra points for a stay anytime award.

So, my question - how far ahead can I book? 12 months? 11 months? Is there an exact number of days?

I think for most Marriotts you can book reservations around 350 days out.

Unfortunately, though, based on some recent posts in this forum, not all hotels are putting their awards inventory into the system at that time. So if you can make a normal hotel reservation for something 350 days out, but there doesn't seem to be any Standard or Anytime awards available, you might want to call the Hotel up directly and ask them about how full they are.

Most hotels allow booking 50 weeks out and the week usually flips on Saturday night.

(Notice I said most )

every Sunday morning inventory is added making it 52 weeks out

I've generally not had much of a problem booking 2 or 3 months in advance. Therefore, I didn't think it was such an issue booking reward properties (though I would understand certain properties, like Hawaii, being hard to get).

Am I just really lucky, or am I booking properties that are not very popular?

For some markets, it is not hard to get award availability on short notice. It depends where you want to stay. Places where Marriott has a lot of rooms to fill with varying demand like the Washington DC area are easier to get awards. It is much harder if you are looking for free rooms at the FS hotels in Paris, NYC, Hawaii, or places during high season when everyone wants to go (for example, Florida and properties near ski resorts in the wintertime).

The dates for reward travel also determine the difficulty of getting an award. For instance, it is a lot easier to get a free room in NYC after New Years than before Christmas. If you want to get an award at a property where a lot of families go during school breaks, it could get difficult.