How long does a statement of attainment last if yu choose to go back and study same course?

A Statement of Attainment does not have an official expiration date; however, its relevance may decrease over time, especially if the course content has changed. If you return to study the same course, some institutions may recognize prior learning and allow you to build upon your existing qualifications. It's best to check with the specific educational institution for their policies regarding the recognition of previous statements.