IaaS service because building out a full infrastructure for unpredictable requirements isn’t economical. 

✓ Organizations may have a continuing need for additional compute or storage resources over time and can use a private IaaS to make those resources available on demand for a variety of projects. For example, additional public or private resources may be required as hardware reaches end-of-service life. 

✓ Some organizations are using IaaS for cloudbursting  when there are unexpected or planned high-load periods. The flexibility of using IaaS means that the company doesn’t have to overinvest in hardware. These companies must be able to adapt to higher loads to protect themselves. 

In the case of PaaS, companies find that PaaS can offer value during development and deployment, instead of having to purchase many different tools. By providing the underlying software infrastructure, PaaS can reduce organizational costs. PaaS reduces many of the costs involved with the traditional application development and deployment model including server and storage overhead, operating systems, workload and performance management software, network bandwidth, software maintenance, and support personnel. However, there are also some indirect value drivers for PaaS. These include 

✓ Reducing careless mistakes:  Mistakes, such as someone forgetting to load a configuration file can take a week before the problem is identified. Such mistakes add up to time and money wasted and cause deployment delays. With PaaS, such mistakes are reduced because the platform has been tested and is known to work. These successful and well-understood patterns are an important benefit of a PaaS. 

✓ Lowering skill requirements:  Perhaps only one or two people in an organization have the skills necessary to work with a certain kind of middleware. By providing the development tools and middleware, PaaS lowers the skill level required to deploy applications and removes the bottleneck that can form waiting for one specific person’s assistance. 

