One of the key benefits of hiring a Greater Toronto area SEO agency is that we will not only take care of the technical aspects of optimization needed to improve your Google rank. We do that with details that are relevant to this geographical market.
It is certainly possible to do your search engine optimization; however, given the extent of heavy lifting needed to get to page one of Google, this is likely to be an onerous task. Besides, Google keeps moving the goalposts on a nearly continuous basis. You, therefore, need to work with a specialist who has the expertise and bandwidth to deliver the work needed to get you to page one of Google.
Another reason to hire a local company is that search engine optimization is done best for a local market. In this market, you have to contend with competitors only from this market. In a national or global market, you need to contend with national and global competitors. If you are offering your product to a global audience, then you need to optimize for search engines on a global scale.
On the other hand, if your market is local, then your optimization needs to focus on the local signals that are assigned value by Google. Google understands the local versus global differentiation, and on specific searches gives priority to local companies so that they show up on top.