when to use a sub domain vs a domain

When to use a subdomain instead of a domain 

• The debate between a domain and a subdomain has been there for years. What most people do not understand is that creating a subdomain has no significance unless you create a totally different product line or your company has launched a new product and has a totally new content and would like to use a catchy subdomain
• One good reason for using a subdomain is that you would look more authoritative to users However take into account that it is much less expensive to use a subfolder and and have slightly less panache that it is to educate through branding an advertising
•  However a subfolder will work 99% of the time.Keeping content on a single root domains and single subdomain gives the maximum seo benefits as the engine passes on all the positive metrics , including the backlinks and the PR earned by the site
• Subdomains are definitely not worth the time and  not a popular choice if SEO is a prime concern. Subdomain may iherit the ranking benefits and benefits of the root domain they are hosted underneath, but they do not always do Subdomains may be used when keyword usage in the doman name is of critical importance For example own usedtoyotatrucks.com, you can pull in quality search traffic for the specific term used toyota trucks with a microsite