I do a lot of free Facebook posts and paid promotions.
I have people tell me "I saw your Facebook post" and book jobs.
Was it free or paid, who knows?
I also have past customers and friends who mention that they have seen my posts pretty frequently. So I do know people are at least seeing them.
I post once a week to about 55 different groups, in addition to the paid posts.
Yesterday I created a promotion for a unique service. This is going to let me know if the post worked or not.
I do have a friend who does paver sealing and cleaning and gets a ton of business from Facebook. But, he is pretty scientific about it and tracks ads and fine tunes them along the way.
But even at that, when he does have a successful fine tuned ad, it will peter out and he has to start again.