What is your route from a first hatch to the next rebirth?

I’m interested in a practical first-to-next-rebirth route. Tell us which egg you opened, which speed or jump threshold mattered, and when you stopped upgrading the current pet.

For an early rebirth, compare the coins spent on the first egg with the pet's actual movement in the next area. Which upgrade was the last one you bought before saving for rebirth, and what would you change on a fresh account? Compare the pet index.