Until just over a few years ago a mobile site would have to be served up on a separate url meaning your business website would be split in to two different sites. This would mean a serious business website would have to be developed twice and that means twice the costs!
Only spending money to develop one single responsive website rather than a desktop website and a mobile specific website is going to cut down the overall development costs. Not having to manage two separate websites is going to cut down the time it takes to potentially and perpetually administer the content. Adding new content in one place means adding content in another as well so adding content to just one site means you can reduce the time and therefore reduce administration costs.
Obviously developing two sites means having to host two sites as well, after all those development costs can you really afford the additional hosting costs? With a responsive website on a single url you only have to host one website so that’s another saving, not to mention the headache of monitoring double the technology stack! I’d much rather have one thing to worry about than two.
So if you’re asking yourself “Why do I need a responsive website” well, because in my opinion you’ll be saving money, although the initial expense for a responsive website might feel costly, in the long run you will save money on less development costs, less hosting costs and less administration costs – that’s why!