Double jaw+zygoma reduction: Is it better to do both surgeries separately?

Is it better to do both surgeries separately. If yes, why is it? I am worried about zygoma sagging, deciding between push in method is better than shaving(L cut). If push in is better, I have to do it separately. I'm F, late 20s, only 2 options possible. 1)do both together at early 30s, avoid surgeries at mid 30s. 2) do separately, span out (30s-35) age. Which 1 is better choice.please advice,thanks.