You mentioned this concern in the slides, especially at the very end. What's your current situation in this regard, both from the personal (worry, sleep lost etc.) and the technical side (high availability, outsourced admin etc)? And what's your outlook on that for the near future?
This is one of the major benefits of having a "proper" startup, as you can share the load. For a bootstrapped single founder, it's a pretty big issue – or at least it appears to be one (most web apps don't really need five nines – unless it's your web app).