When I write todo items in a list, I typically think it's best to do the oldest ones first. I suppose I think of todo items like cans of honey in a pantry. I want to open the oldest ones first, because they're the closest to expiring.
However, someone recently opened my eyes to a good case for doing the most recently added todo items, which is this: the very fact that the oldest items have been on the list so long without being done is some evidence that they don't need to be done. Whereas such evidence has not been accumulated about the most recent items.
Ultimately I think the list should be prioritized somehow, but this was an interesting thought.