No one has any idea. But a number of buyers are tempted to sign up for five years of Internet hosting. This is lunacy. It's impossible to create boundaries or service level agreements for an unknown process. Suppliers prefer long-term contracts because the commitment allows them to invest their own capital in the process.
Shorter contracts require shorter amortization periods.
At Everest, we advise our customers to develop long term relationships but sign short term contracts. Make sure the contract duration is appropriate. You do this by matching the term with the life cycle of the process and staying in tune wth the natural changes of the business cycle. For example, we worked with an insurance company that was a third party administrator. The contract it signed was for seven years because the supplier was administering the claims for a closed group of policies that would expire within seven years.