Usually, it’s is very useful to have a solid domestic sales to form the basis of a good exporting business.
Overseas buyers usually find it reassuring if a potential supplier company has a successful domestic business. That also ensures that your business processes are in place and well tested. Developing your export markets take a lot of financial resources, so it is very helpful to have cash flow and the working capital from your domestic market.

You need to have the right people to run an export business. That may mean, that you will have to hire new staff.
Expanding to exporting takes strong financial resources as you will have to cover international marketing, travel, possible product modifications, legal advice with deals and documents, to mention some of the possible additional costs.

More management time may be consumed to developing an international business than developing business at home. And it takes not only a deeply committed sales staff and directors.
Exporting will involve at least the management across the business.

Formal business planning may not be that familiar, especially if you have a smaller company focused on the domestic market. However, all that will change once you start exporting. Planning is vital, if you are to move your business to a different level.

How do different foreign markets operate? What kind of culture clashes are expected? What kind of export documentation is needed? How long does it take to receive payments from different parts of World? How to manage foreign currency? You will need to learn about a wide range of issues in order to export successfully.