We requested ours back 12 months in advance of our wedding date because we had to pay for all of the events on a per person basis 4 weeks prior to the wedding and we figured there would be a couple of people we would need to track down. Though I still to this day have never heard back from quite a few people... I didnt know people could be so rude! It's just not that difficult to check "no" and send it back in the already post marked envelope we provided them.... but I digress... I ordered our OOT items about 6 weeks ago, with many of the items coming from Amazon and we have the prime shipping option so mostly everything was delivered within 2 days of my ordering it.
We leave for our wedding in 10 days and unfortunately just had 3 people cancel, so we are now stuck paying for their dinner at the reception, rehearsal dinner, and cocktail hour as well as all of the OOT bag items we purchased. I almost feel like it is easier and better in the long run to underestimate the total guest number because you can always buy more or add on people last minute, but cant always get your money back