A lot of this is your personal preference. Some of my clients book one - two years in advance to be able save up and having something to look forward to. Some clients call me two weeks before they want to leave. Here's my general advice: 

 For cruises - the sooner you can book the better. For most fares, the deposit is refundable so you have nothing to lose by reserving a cabin. I monitor the rates for my cruise clients to make sure they are getting the best price or the best upgrade. Right now,I personally have cruises on hold through 2016 because I loved the price and the promotion. 

 For resort packages - Flights don't become available until 330 days from departure for many airlines and even less if you want to fly Southwest or JetBlue. If you want a specific resort or a specific room it's important to book early. If you are open - you can wait until about 6 - 8 months from date of departure. The availability of last minute deals really depends on the city you are depart from and the time of year so message me for more specific details. 

 For Disney - Book early. You lock in the room you want.I monitor all promotions and can adjust your booking if the rate drops. 

 How far out do you like to book vacations?