Content
Is most of the current information still accurate and useful?
A redesign is useful when the foundation is sound. A new build makes more sense when the structure, technology or positioning no longer supports the business.
If the site structure works, the content is mostly relevant, the platform is maintainable and the main problem is presentation or conversion, a redesign can be efficient. Keep what is working and improve the parts visitors actually experience.
A new build is more practical when navigation is fundamentally confusing, the site is difficult to maintain, mobile behavior is broken, the brand or service model has changed, or technical debt makes every small change expensive.
Is most of the current information still accurate and useful?
Can visitors find the important pages quickly?
Can the current platform support what you need next?
Does the existing site work well across current screen sizes?
Can speed and stability problems be fixed without rebuilding everything?
Does the site still represent how the business wants to be perceived?
No. If the underlying structure is poor, repeatedly patching it can cost more than a clean rebuild.
Only if the brand itself needs work. A website project should not force an unnecessary identity change.
Usually yes. The domain is separate from the website files and hosting setup, subject to how the project is configured.
No. Search performance depends on content, technical implementation, relevance and many other factors. A rebuild can improve the foundation but is not a ranking guarantee.