In short
Whether an expired domain is worthwhile is decided by vetting. Key criteria are the domain history (prior use, no spam past), the quality and origin of backlinks, topical relevance and possible trademark/name rights. Only after this vetting is a registration an informed decision.
Vetting checklist
- History: how was the domain used before? Any signs of spam or penalties?
- Backlinks: quality and origin instead of mere count (see backlinks).
- Topical relevance: does the history fit your planned project?
- Legal: rule out third-party trademark/name rights.
- Technical: prior indexing, language, country reference.
Tools & limits
Archive and backlink analyses give reference points but no guarantee. A clean, on-topic history can bring advantages — but does not guarantee them (see expired domains & SEO).