No one would argue the importance of availability. However, when asked to justify the cost of additional hardware to support improved availability, many people do not know how to build a case.
The following steps describe how to estimate the value of your information services:
Develop a list of the major services and
solutions that your system provides. Your system exists so that
end users and solutions can accomplish tasks that are critical to the operation
of your business. The systems provide solutions to a business function. If
the system is unavailable, the business function cannot be completed or is
significantly degraded to the point of causing the business lost revenue or
increased expenses. 
- Assess how much it costs you when these
services are unavailable. Each application or service has a direct
affect on business functions. You need to determine how these business functions
would be affected and what would be the overall cost to your business.
- Look at direct costs versus indirect costs. Direct costs are losses that can be traced directly to a system being unavailable. Indirect costs are those that are incurred by another department or function as a result of an outage.
- Consider tangible costs versus intangible costs. Tangible costs are those that can be measured in currency. However, there are other costs that are not measured with money, such as market share, lost opportunity, and good will.
- Analyze fixed costs versus variable costs. Fixed costs are those that result from a failure and are the same, regardless of the length of the outage. Variable costs are those that vary, based on the length of the outage.