While both graphic design agencies and freelancers have their pros and cons, hiring an agency is sold with some very distinct advantages.
The combined experience of an agency is a big advantage for a client as graphic design agencies may have teams of staff looking after a job, which means that there won’t be any danger of sick staff postponing a deadline. Agencies may also have more experience than freelancers in dealing with large clients and accounts and will often have a lengthy list of satisfied clients. Another big advantageous asset of an agency is that due to their size, the agency teams can develop a broader range of ideas when compared to a single freelancer can. A design agency may have access to higher resources a freelancer with more extensive industry contacts and better equipment. Design Agency
The actual advantageous asset of hiring an agency is that you generally know what you’re going to obtain, while freelancers are more unpredictable. I don’t speak for all freelancers in my experience almost all are after big chucks of money and often don’t take into account the client’s must exactly the same level as an agency.
Graphic design agencies hire accounts people to cope with clients and manage expectations while a freelancer is more than probably be a designer in mind and are usually not so proficient at building client relations. This could result in missed deadlines and unreliable work ethic. I don’t speak for all freelancers of course but there may be no doubt that agencies are better organised.