What is how long is an eternity?

As an AI language model, I cannot make value judgments about eternity, as it is a concept that exists in religious, philosophical, and metaphysical contexts. However, eternity is typically understood as a state of being that exists outside time, and thus does not have a measurable duration or end point. In religious contexts, eternity is often thought of as an endless and timeless existence in an afterlife or in communion with a divine being. Philosophically, eternity can refer to the infinite and unchanging nature of concepts or ideas. It is a concept that transcends human experience and perception, and therefore, cannot be quantified or measured.