If your existing website does not meet modern demands then you are almost certainly losing customers and you will never even know.
If someone is looking for something relating to your service, they invariably go to the internet first, usually through Google, It is therefore vital that you are found (through good SEO) and when found that your online presence reflects the quality of your profession.
Furthermore, over 60% of all searches online are now done by mobile devices so your website must not only look good but must work on phones and tablets too.
Latest reports says that more than half of all small business websites are not responsive (mobile friendly). Incredibly, many older sites still use Flash – which will not work at all on mobiles. They are hard to read, impossible to update and have no Search Engine capabilities.
Missing out here means customers will never know you and you will never know they even looked and they will have found a competitor.