One of most important thing to consider when deploying Sitefinity is the Sitefinity web hosting environment. There are million option out there to host Sitefinity application. You can host in shared Sitefinity web hosting, on a dedicated Sitefinity web server or in a Sitefinity web hosting cloud. It all comes down to how much control you like to have on your live site and what is your budget.
If you have mission critical Sitefinity application that you like up all the time even in case of server failure or you need to auto scale the application. Then in this case you have to go with a cloud solutions. With cloud environment you have full control over your Sitefinity hosting server and can setup auto scale and even setup load balancing with your application.
For Dedicated server Sitefinity web hosting it will be more costly to host both Database and Web server. I will not recommencement hosting both on the same server for busy site.
If you have a small site with few users vising your site each month then you can go with shared Sitefinity web hosting but not a good solution.