Doctor Who: 8 Reasons Donna Noble Saved The Doctor
1. Donna's Legacy (The End Of Time)
This speaks more to the lasting effect that Donna had on The Doctor, from meeting him during her first wedding, to his appearance at her second. Throughout their time together, Donna and The Doctor saved the galaxy and each other.
With The Doctor slowly dying from radiation poisoning, he takes a last victory lap through time, visiting each of his friends as he goes. He visits Wilf, Donna's granddad, as Donna walks down the aisle - delivering his last gift to them in the form of a lottery ticket (bought with a pound he received from Donna's deceased Dad, Jeffrey).
Although Donna can ever remember her adventures with The Doctor in the TARDIS, he takes the lessons he learned from her with him. Always save someone, if you can. And when you can't - try anyway.
Donna Noble crafted The Doctor as we know them today - her legacy is the many victories they have had.