The primary factor is dependent upon whether you plan on using blog.example.com (a subdomain install) or example.com/blog (subdirectory install). If it’s the former, nothing additional is needed; it will just live in its own top level install. If the latter, then a reverse proxy will be required to enable subdirectory access on the same domain.
Subdomains
If your content ranges across multiple topics, you may want to consider a subdomain structure. Larger companies that have a hand in a variety of areas, industries, forms of entertainment, etc. may find a subdomain structure perfectly fitting. A subdomain URL would look like: blog.example.com. Subdomains are also less technically intensive, which helps explain their popularity.
Subdirectories
If your central focus revolves around a singular niche (like many of us), subdirectories may better suit you. Ultimately, maintaining a subdirectory file structure is generally favored for SEO purposes by directing more traffic to your main domain. A subdirectory URL would look like: example.com/blog.
Subdirectories can involve additional security and maintenance overhead, drawing more complexities and risk onto your team. Luckily, at Pagely, we can support and maintain a WordPress reverse proxy for you. Whether both end points are being served from your Pagely VPS or just one, our WordPress engineering experts have done it all and can help you, too.
Other Factors to Consider
Other factors such as page speed have an impact on your SEO ranking as well according to Google (not to mention your user experience). It’s important you have the right caching and other optimizing tools in place for gaining the most performance from your codebase, supported by a competent staff specialized in WordPress hosting.