Must....Know.....
Larvesta Eggs hatch in 40 Egg cycles.
Generation V/VI 10280 steps
Generation VII 10240 steps
Generation VIII/IX 5120 steps
List of Pokémon by breeding attributes (Bulbapedia) Decreasing Egg cycles (Bulbapedia)
ah, the Larvesta that bacomes such a beautiful Pokemon, Volcorona.... it takes 10455 steps to hatch it.
It takes 10,240 steps to hatch. Source
Also, click here for instructions to get a Larvesta egg. Be sure to have a pokemon with flame body in your party to speed things up! Hope this helps!