A plain-language explanation
The age of a domain is the period counted from its registration or documented use, which in itself is not a guarantee of high visibility or quality of the website.
Where it helps in practice
Domain registration age is historical context and does not guarantee visibility, trust or present site quality.
The decision before implementation
When acquiring a domain, inspect usage history, indexation, links, penalties, naming rights and ownership continuity rather than buying age.
How to verify the result
Review archives, Search Console, backlinks, legal status and current reputation regardless of years.