In digital marketing, one of the main constraints is your monthly budget. Generally, your boss or client wants to see you spend exactly the amount budgeted each month. This is one half of the problem. The other half is that Google doesn’t allow you to set monthly budgets, only daily budgets. Unfortunately, the daily budget isn’t even a strict limit. If you look at Google’s TOS, you’ll see that Google may spend more up to 2x your daily limit if you’re paying for clicks, and more than 2x your daily budget if you’re paying for conversions –They don’t give a limit. They do say that “you won’t be charged more than your average daily budget multiplied by the average number of days in a month” but I’ve read support issues where they have clearly gone over this limit and not refunded the difference. Underlying this policy is the real dynamics of supply and demand. In markets, long periods of steady, predictable demand can be interrupted by periodic spikes in demand driven by market conditions, events or other advertisers. If you’ve never woken up the next day to the sickening realization that a random event busted your budget, it’s not a great feeling.
At Zavient, we’ve taken a proactive approach to this for Google. We’ve built out the “Campaign Budget Optimizer” (CBO), a program that checks your total spend for the month every day, compares it to your budget, and calculates how much left you have for the month. It then calculates a daily budget for each campaign based on how much budget you have left. This program essentially resizes your remaining spend so that you gradually decrease your budgets as you progress through the month.
We’re also building a “circuit breaker” program that monitors hourly spend, and if spend ever gets to 2x daily budget, it pauses all campaigns and sends out an email alert. While this system obviously involves tradeoffs, in our experience it’s better to be overly cautious than overly aggressive.