Whenever you cease that activity, you cease being a scientist. A distressing amount of pseudoscience is generated by actual or self-proclaimed scientists, in several ways we need to discuss. A scientist almost invariably winds up doing pseudoscience when he moves out of a field in which he is knowledgeable and competent, and plunges into another field of which he is quite ignorant. A scientist becomes a pseudoscientist when he defends an idea when all evidence and experiment is against it, because he is emotionally or ideologically committed to it. A scientist who forges data, or suppresses data which do not agree with his preconceptions, or refused to let others see his data for independent evaluation, has become a pseudoscientist.
Science is a high peak of intellectual integrity, fairness, and rationality.
To carry the analogy further, the peak is slippery and smooth. It requires a tremendous effort to remain near it. But any slacking of effort carries one away, and into pseudoscience. From what we have just outlined, one would expect this to happen extremely rarely, if ever. In fact, neither I nor any informed colleague I have ever asked about this, knows of any single case in which this has happened during the hundreds of years the full scientific method has been known to and used by scientists.