A determination method, a control method, a determination apparatus, a pattern forming system, and a storage medium can determine a replacement time of a focus ring accurately and quickly. The determination method is capable of determining the replacement time of a focus ring that surrounds a substrate to increase uniformity of a pattern in a surface of the substrate when the pattern is formed by etching a film on the substrate. The determination method includes measuring a shape or a critical dimension of the pattern; and determining the replacement time of the focus ring based on the measured shape or the measured critical dimension of the pattern.