There is one simple question to determine whether you need a disaster recovery plan: "Can my business continue to function without my Computer System?"
Disaster recovery is becoming an increasingly important aspect of business. As devices, systems, and networks become ever more complex, there are simply more things that can go wrong. As a consequence, recovery plans have also become more complex.

The length of time between the disaster and recovery of your vital applications is a key factor. If your business cannot continue without access to your business data, your disaster recovery plan must take this into account.

The time-sensitive nature of your recovered data can be an overriding factor. If your vital application is a high volume, high change application, recovering week-old data may not be acceptable--even hour-old data may be unacceptable. You may need to recover right up to the point of the disaster.