Professional web designers spend their days creating web sites, building pages, tuning web sites for better click through performance, worrying about accessibility issues, keeping up on the latest's compliance issues, browsers, the latest online products, services, design styles and more.
Tip 1: Don't hire a web development company that doesn't have a great web site. If they're not walking the talk, they're most probably not the help you'll need!
Time is probably your next key issue. Effective businesses are run by people who stay focused on the critical issues of their businesses - products, pricing, location - and delegate other tasks to staff or outsource.
Creating a great web site involves time. Creating branding / logos, page and banner designs, content development through fine-tuning key performance factors. Good web designers save you loads of time and help you focus on your key business goals.