For example, Customs often won't in let products lacking the requisite certifications -- such as a CE Mark if it's trying to enter the European Union -- instead letting pallets sit at the import sheds. And many stores and other resellers won't stock and sell your products because without certain certifications, there's a greater risk of product return. Some unions, and some insurance policies, require products have safety certifications.
Certifications also matter to buyers. Certifications, or the lack of them, may also influence purchase decisions. Many purchasers may want -- or prefer -- energy-savings and other environmentally "green" certifications. Users with specific usage requirements, such as for use in medical facilities where there's lots of stray fluids along with RF-sensitive gear, first-responders and others in high-vibration environments, will also be looking for specific certifications.
If you're a product designer/developer, it's important to understand what standards your product has to meet, tests it has to pass, and documentation it has to have, for your company to sell it in its target geographic and vertical markets.
There are hundreds of thousands of standards globally, prepared by close to 200 organizations. ANSI has, for example, identified about 90,000 for the U.S. But only a dozen or so types apply to a computer hardware vendor.
However, to complicate matters, there isn't -- yet -- one single global standards organization, nor one single set of standards for a given product that apply globally. Many countries and multi-country geographic regions (e.g., the European Union) have their own standards organization.
"Harmonization" efforts like the IECEE's CB Scheme are working to bring things close to "one product, one test, one mark." Meanwhile, even where CB Scheme-certified products get to avoid the time and cost of some redundant tests, vendors applying for certifications in additional geographic regions still can face "homologation" fees reflecting additional tests, paperwork (languages, different reports, etc.) and other administrative costs.
Starting early minimizes certification time, cost, effort
If you were, say, starting a restaurant or building a house without checking with city hall and the various inspectors until just before Opening Day... going back to Square Two or Square One could be expensive and time-consuming, making you blow your budget and miss your market window. Or even scotch the entire project.