Design applications cost of the order of $2000, a fraction of what utility patents cost. They are comparable to trouble-free trademarks in cost. Of course, they protect different things and the rights are quite different from patents, but they can be remarkably cost-effective.
In Canada and the United States, you must file your first application within 12 months of the first disclosure of the design to the public. You cannot register a design after this. In most of the rest of the world, you cannot file after your first disclosure. Best practice: file before first disclosure.
You cannot register a design that someone else has disclosed (whether registered or not) before.
A design application must be filed in the name of the owner of the design – which may not be the designer if the designer was hired to design or an employee.
If you only make a few articles, you may be able to rely on copyright protection. But if you make more than 50 copies of your design you cannot rely on copyrights, and design registration is required.