The timeline depends on where you start. A business with an established domain, decent reviews and a site that just needs pages and cleanup can see movement in six to eight weeks. A brand new domain in a competitive metro is a twelve month project before it holds anything valuable. Honest agencies will tell you which one you are after looking, and they will be specific about what changes in month one versus month six.
Here is what should happen anyway. Month one: audit, profile cleanup, technical fixes, the first service pages. Months two and three: the rest of the service pages, town pages, review flow running, early ranking movement on low competition terms. Months four to six: the competitive terms start moving and lead volume becomes noticeable. After that it compounds, because pages that earn links and reviews keep gaining instead of resetting when you stop paying for clicks.
Use the waiting period to hold them accountable on output rather than outcome. You cannot control when Google moves, but you can absolutely check whether twelve pages got published and the profile got worked. If month three arrives with no new pages and the explanation is that SEO takes time, time is not the problem. And if you need leads this month, run ads alongside and treat SEO as the thing that lowers your cost per lead later.
Send the site over. We will tell you what is broken, what you could rank for, and whether AI search knows you exist. No charge and no pitch deck.