Insurance coverage is either occurrence based or claims-made. Most "errors and omissions" coverage is claims-made.

Occurrence based coverage is tied to the date of the event/accident causing the claim. The policy in effect on the date of the event/accident is responsible for defense and indemnity. If an event/accident occurs during the term of an occurrence policy, that policy is usually responsible for future claims.

Claims-made policy coverage is triggered by the date you first become aware and notify the insurer of a claim or potential claim. The insurance policy in force on the date you become aware and give notice is usually the insurer who is responsible for defending and settling the claim. A claims-made policy, however, must be in force on the date you first become aware of a potential claim to provide coverage.

All coverage for prior services stop once a claims-made policy is allowed to expire. If you retire or stop providing training or evaluation services, you may want to keep your claims-made" policy in effect at least until the next required legislated time frame for training/evaluation of the operator has expired in those locales where you have trained or evaluated. You may be able, in some cases, to add a special endorsement to your current policy to extend future coverage.

With all insurance policies, read and understand your policy and its requirements. You may think you are covered when in fact you are exposed to liability because you did not comply with certain stated requirements.

Insurance is a complex subject and an area where I claim little expertise. My advice to forum readers is to discuss your needs with your insurance agent or preferably several different agents. I also advise that you read the fine print in your current policies and learn the requirements the policies impose on you to ensure coverage.

Google: UNDERSTANDING CLAIMS-MADE INSURANCE for a good four page overview from eqgroup.