These are the questions that frustrate most of the business owners who want to get a responsive website designed for their business. The answer lies in the type of business you run and the audience who visit your website. Simply put, responsive web design is not for everyone. However, for most of the businesses who have younger audiences that browser their site from smartphones, iPads and Android devices, it makes much more sense to go for a responsive web design.
Find out your site usage patterns in Browser and OS report of your site's Google Analytics account. If a considerable size of audience is flowing through the iPhone/iPad channel, it is time for you to go responsive.
For websites that already have a mobile version, it makes sense to go responsive too as the need of managing two separate sites will no longer be there.