OMG in Gallifreyan I'm 30 next year!
Noooo! I've only been 20 for 3 full days
My wife just pointed out that the Doctor is 909 years old, but is that Earth years or Gallifreyan years, and in which number system?
If we assume it's Earth years as all time measurements in Doctor Who are usually in Earth time, then in the Gallifreyan number system, he's 2436 years old in the base-7 Gallifreyan number system!
Maybe that's the explanation for the Third Doctor claiming his life covers "thousands of years"