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Typically, a new version of the Enterprise is built or renamed as a ship of the latest and greatest cruiser-type class of ship available. Realistically, of course, the Enterprise isn't necessary the first ship of the latest class to be put into service since an Enterprise from the previous class most likely already exists. 

For each iteration of the Enterprise in the primary universe that we know of, how long was that Enterprise in service while a newer cruiser class that would make for an acceptable replacement was already in service?

Typically, a new version of the Enterprise is built or renamed as a ship of the latest and greatest cruiser-type class of ship available. Realistically, of course, the Enterprise isn't necessary the first ship of the latest class to be put into service since an Enterprise from the previous class most likely already exists. For each iteration of the Enterprise in the primary universe that we know of, how long was that Enterprise in service while a newer cruiser class that would make for an acceptable replacement was already in service?

Typically, a new version of the Enterprise is built or renamed as a ship of the latest and greatest cruiser-type class of ship available. Realistically, of course, the Enterprise isn't necessary the first ship of the latest class to be put into service since an Enterprise from the previous class most likely already exists. 

For each iteration of the Enterprise in the primary universe that we know of, how long was that Enterprise in service while a newer cruiser class that would make for an acceptable replacement was already in service?

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How many years was each Enterprise in service while eclipsed by a newer cruiser class?

Typically, a new version of the Enterprise is built or renamed as a ship of the latest and greatest cruiser-type class of ship available. Realistically, of course, the Enterprise isn't necessary the first ship of the latest class to be put into service since an Enterprise from the previous class most likely already exists. For each iteration of the Enterprise in the primary universe that we know of, how long was that Enterprise in service while a newer cruiser class that would make for an acceptable replacement was already in service?