What "99.9% uptime" actually means
A 99.9% monthly uptime guarantee still allows for roughly 43 minutes of downtime per month. 99.99% narrows that to about 4 minutes. Always read what the provider actually credits you if they miss the target — many only offer service credits, not refunds.
How to verify a host's real uptime
Provider-reported uptime is marketing copy. Independent monitoring services and long-running reviews are far more reliable signals than a badge on a pricing page.