The time of year when your birthday falls is a big factor because flights and accommodation costs will be significantly higher in the summer and school holidays. I reckon I can get 3 weeks holiday outside those times for the same price as 2 weeks in high season.

My top tips would be to be flexible on dates and grab bargains like flight sales when they come up. Obviously, if you want to be in Florida on the date of your birthday, your options are more limited.