Doing something right the first time is better than going back to correct it later. These words are particularly persuasive in the product usability arena. Research has demonstrated that relative to correcting errors in the design phase, it costs businesses 10 times as much to correct errors in the production phase and 100 times as much to correct errors once the product has been deployed.
Thus, it is critical to incorporate user-centered design in your development lifecycle as early as possible. But, some business or product stakeholders may not see value in user-centered design to begin with. So what are the benefits of user-centered design?
Reduced Costs
Usability investments reduce development costs. The rule of thumb in many usability-aware organizations is that the cost-benefit ratio for usability is $1:$10-$100. Once a system is in development, correcting a problem costs 10 times as fixing that same problem in design. If the system has been released, it costs 100 times as much relative to fixing in design. 
Integrating human factors input early in the product development lifecycle is very inexpensive, especially compared with the staggering costs of moving ahead without it. "Speeding up development is a key goal for integrating usability into product development. A one-quarter delay in bringing a product to market may result in the loss of 50% of that product's profit." (Bias & Mayhew, 1994). Maintenance efforts can be costly, particularly if a simple usability assessment or research initiative would have avoided the need for additional development. "One [well-known] study found that 80% of software lifecycle costs occur during the maintenance phase. Most maintenance costs are associated with 'unmet' or 'unforeseen' user requirements and other usability problems." (Pressman, 1992)
Increased Efficiency
The benefits of user-centered design are not limited to customer products; many organizations purchase or develop applications for their employees. For example, an intranet that is easy to use will help employees complete their tasks more quickly, resulting in increased productivity and a cost savings for the employer. On a corporate intranet, poor usability means poor employee productivity - any investment in making an intranet easier to use can pay off by a factor of 10 or more, especially at large companies.
Ease of Use
Capturing the attention of and earning the loyalty of your customers is critical to your business. Offering your target users a solution that meets their needs, improves their productivity and is easy to use is the simplest way to assure your product's success. A commitment to ease of use will allow your organization to exceed customer expectations and result in better than anticipated earnings.