The short answer
Set acquisition budgets from LTV and contribution, not a low CPA — thin retention in a new market can make even cheap acquisition unprofitable.
A common cross-border mistake is optimizing for the lowest CPA in a new market. CPA alone says nothing about whether those customers stay, repeat, or refer.
LTV (lifetime value) reframes the question: how much can you afford to acquire a customer, given the revenue and contribution they generate over the whole relationship in that market?
In a new market, retention often starts thin because trust, support, and habit aren't established. A 'cheap' CPA can still lose money until local retention matures.
The disciplined approach ties budget to LTV and contribution, separates direct, modeled, and assisted attribution, and reads results over a stated measurement window — so spend scales on evidence, not vanity volume.