Study case back in 2013, a trend for 2014, definitely a norm for 2015. We are talking about responsive design. Over the last few years responsive design has solidified itself as the new standard for web design in general and WordPress themes in particular. Sure, there are still arguments about implementing responsive design but in fact more and more sites are changing their image implementing ideas in that direction.
With the number of Smartphone users’ hits 1.75 in 2014 which is further expected to increase by 22.5% in 2015, is a significant market part that cannot be ignored. Many of your potential clients are looking for you while on the move. Your website should be able to give them the information they will be looking for so you to have the opportunity to turn them into clients.
Maybe you have a really good reason for not using responsive design?