How I scale a winner without killing it: the 20% ladder
The fastest way to murder a profitable campaign is to double the budget overnight. Here's the slow ladder that actually holds ROI.
The setup
Winning campaign: $50/day spend, $11 CPA on a $14 payout, ROI +27%, stable for 5 days.
The move
Two lanes, run in parallel:
— Vertical: raise budget by 20% max per day, only if yesterday's CPA stayed under target. $50 to $60 to $72. Anything above 20% retriggers the learning phase and resets your math.
— Horizontal: duplicate the winning ad set into 1 new geo and 1 new placement at $20/day each, fresh, not as a budget bump.
The numbers
Vertical lane reached $124/day over 8 days, CPA crept to $12.10 (still green). Horizontal lane found a second geo at $9.80 CPA, better than the original.
The lesson
Vertical scaling compresses margin as you exhaust the cheap audience. Horizontal scaling finds new cheap audiences. You need both, and horizontal is usually where the real money hides.
What I'd do differently
I moved vertical too aggressively on day 6, CPA spiked to $15 for a day, lost ~$40 reclaiming stability. Cap it at 20%, period. Illustrative numbers.
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