Typically within the first 1-2 days, though you should be aware that the first two weeks include a ramping period that takes time to see consistent results.
It is normal when starting to have some days where you may get multiple leads and some days where you get none. This consistently will improve overtime due to something called 'Pixel Optimization'
Advertising Optimization
If your Facebook Ads show higher cost-per-lead results within the first 72 hours of starting a new campaign, do not be alarmed.
We follow a protocol called the “72 Hour Rule”, in which we do not take any data
given to us by Facebook seriously within the first 72 hours due to the unstable
nature of the Facebook Ads algorithm.
For example, in some cases your first day of performance will be amazing while it
drops for the next two days and then goes back to being a high-performer. Imagine,
what would happen if we saw that it tanked on the third day and then turned it off?
For this reason with instability, we ask that you trust our advertising process and
give campaigns the time they need to optimize.
Every single client in Book More Showings is built a fully-fledged, Conversions API
system which uses the Facebook Pixel to generate the highest quality Facebook
leads. In simple terms, we have an advanced server setup on Google, that helps you
get better leads throughout time. You’ll notice that the longer your campaign
remains active without being touched, your lead costs will go down and quality will
steadily increase over time while decreasing cost-per-lead.
The worst thing we can do is interrupt this process by making adhoc changes within
the first few days of a campaign launch, because we don’t like what the numbers are
showing us. For example, have a look at two different campaigns below:
The maturation process of a Facebook Ad campaign with our system is typically 1-3
weeks or $750 CAD spent (whichever comes first) as long as the campaign remains
unedited. We ask for your patience and trust while your cost-per-lead goes down
overtime.
Further Reading: About The Learning Phase - Meta Business Help Center