The most straightforward path is sticking with a single weekly shot, only breaking it into pieces if some particular problem actually calls for it.
A handful of scenarios justify splitting things up. First, reactions that hit hardest a day or two after injecting, where softening the peak concentration eases that, assuming the overall amount stays the same.
Second, hunger control fading out before the following dose arrives, particularly when just bumping the total higher hasn't resolved it.
Third, and this comes up less often, breaking things into smaller, more frequent shots can be a lower-risk way to ramp up quickly, but that approach demands real understanding of what's actually happening, and honestly it's rarely called for.