Hey Dmitry,
Yes, we don’t recommend using a caching system as this can cause issues when the master ref is changed on every document update, this can cause websites to break.
Make sure you are using your CDN endpoint to offer your website extra protection and speed, for example https://your-repo-name.cdn.prismic.io/api/v2.
Also like Paulina said the platform is very stable. We have exceeded the Uptime of 99.9% for the past 26 consecutive months and are committed to maintaining this standard.