Prove the unit before adding budget
Scale multiplies whatever the campaign already is. If cohort economics are unproven, additional budget multiplies the loss rather than the learning.
Increment, measure, repeat
Budget increases in controlled steps with a measurement pause between them make it possible to see where efficiency begins to break, instead of discovering it after a month of spend.
Expand the surface, not just the spend
Sustainable scale usually comes from new audiences, new creative concepts and new markets rather than from bidding more aggressively into the same inventory.