Design for using your own API

So I’m planning to use APIs for my host app. But the APIs are built such that it requires a sessionkey for every request.

When is it appropriate to start using the next revision of a tool when dogfooding?

Specifically, I am working on a tool that integrates a DVCS and build system, but I image the challenge I am facing would arise for anyone developing a “meta” tool (compiler, VCS, build system, test runner, etc.) that they wish to develop through “dogfooding”.

Should a web app for a service access its data via its own API or directly?

I’m building a service that will consist of mobile and desktop apps, which will require me to build my own RESTful web API to easily keep the data for the service in sync. I am also building a web app in Ruby on Rails. Initially I plan to host everything on one server due to cost.

Is there a metric for software stability for packages with few users?

Software packages usually get a label for stability, like ‘alpha’, ‘beta’, or ‘stable’, next to their version string.