When planning a preservation project that might take ten years or more, it is obviously important to think about how circumstances might change over time. An archive is unlikely to be in the same position in five years time as it is in today, let alone ten.

From a business perspective, changes over time can be hard to predict, for example:

• An archive might acquire one or more new collections, which in turn increases the demand for preservation.
• New funding initiatives might arise and allow much more to be achieved in a preservation project than was originally planned. The reverse could happen and sources of investment into the archive might dry up.
• The user needs for archive content can change over time, especially in broadcasting, if they depend on what’s ‘fashionable’ at the time.
• Public perception and government policy can change, for example resulting in new initiatives for increased archive accessibility for public benefit.
• New technologies might open up new distribution channels and markets and hence change the user base of the archive.

For all these reasons, it is important to have a flexible preservation plan that can be revisited and revised on a yearly basis to allow change to be managed. The plan should take account of time dependent factors as best as possible. These include:

• Technical obsolescence
• Content degradation
• Inflation and deflation
• Market timing

These are described in more detail in the sections below.