Design agencies and related businesses have connections and the experience to choose the right sign company that fits the project. However, the average business owner might only seek the services of a sign company once or twice, making the decision more difficult and overwhelming.
Sign companies can specialize in design, installation, production, maintenance, and even the securing of permits. Some will offer all of the those services, while others might only offer a few.
Choosing the right sign company is best summed up by the following excerpt from the article How to Choose a Sign Company (https://www.signs.org/SignIndustry/Signage101/HowtoChooseaSignCompany.aspx):
Shopping for a sign company is just like shopping for any other company. Look for signs you like and ask the business owners to tell you who built it for them. Look in a directory such as the Yellow Pages, or check out the various organizations referenced in this booklet.
It is a good idea to comparison shop, look at examples of signs the company has built and decide whether the company is capable of meeting your particular needs. Cost, quality, and follow-up service are obviously important considerations, as well as the variety of other services that may be included. For instance, securing a sign permit can be a challenge to the inexperienced small business owner; an experienced sign builder will handle this process more easily.