How it works
While it lasts, the results are unstable and there is no judging by them. Learning is restarted not only by a change of strategy but by any noticeable edit to the goal or the budget — which is why frequent edits keep a campaign in permanent learning.
Our practice: we move the target ROAS by no more than 15% at a time and no more often than once every one or two weeks, and the budget by no more than 20% at a time.