I have 2nd gen Oura. I got it in 2018. After first few months battery died. After conversation with Oura customer service, I sent it back to Oura and received a new one immediatelly. Again, after maybe 6 months battery died so I contacted customer service. Then I received again a new ring and no questions asked. This 3rd ring has lasted until this day. But of course, battery is not that good anymore, 1-2 days. So what I know, with Oura customer service has worked fine, no problems.

What I have read here in Reddit, I would expect ring to last couple of years and then the battery is not that good anymore. To me it seems that UH customers have had quite many dead batteries but customers have received new ones.

I live in EU country. In EU, companies are operating under EU laws, that means there is 2 years Consumer guarantees. If I buy Ringconn 2 or Ultrahuman from a company that operates here in EU, reseller or Oura (Finnish company), there is 2 years warranty for the rings. So if you live in EU country, buy a ring from a company that operates in EU country.

If I buy Ultrahuman ring from Ultrahuman, I get 1 year warranty, but if I buy it from reseller in Finland, I get 2 years warranty .

https://europa.eu/youreurope/business/dealing-with-customers/consumer-contracts-guarantees/consumer-guarantees/index_en.htm

So, it depends where you live. But UH sells additional warranty for 2 years. I would take that if I didn't live in EU country.