What do you usually do when you see that one of your ad sets is performing better than others? You probably spend more on it to make it roll more to drive
Based on Pixel Purchase
Cost Per Acquisition, whatever it is in your case, purchases or mobile app registrations is the best indicator to make decisions on increasing budget.
Purchases (Pixel) > 1 (Last 3 Days) and
Cost Per Purchase (Pixel) < $50 (Last 3 Days) and
Spend > $0 (Today)
That means while you have purchases in the last 3 days and your Cost Per Purchase stays lower than $50, you can keep increasing your budget.
Based on ROAS
Return On Ad Spend (ROAS) = Pixel Purchase Revenue / Spend
ROAS > 3 (Today) and
Spend (Today) > 0.5 * Daily Budget (Today)
In Reveal you can compare metrics and base actions on that. In the above example we compare Spend with your Daily Budget.
So if your ROAS is strong (revenue is more than 3x times bigger than spend in our example) and you've already spent half of your daily budget – your budget is going to be increased to get you some more of that well-delivering ads.
Note: In Reveal you can decide how often you want to change your budget: it can be as often as every 15 minutes or just once a day. You can also change the budget by a specific amount or percentage.