Should task based interfaces be implemented all-the-way or partially where it makes sense?

We are considering implementing task based interface for our new application. What we are not sure about is should we stick to it consistently for all of our screens or should we leave CRUD screens at some places?

I know I am asking an abstract question but that is actually on purpose; to get an idea about task based interfaces aims and best practices. Are they something one should try to enforce everywhere (if decided to go with it) or "where appropriate"?