I think its knowing what's reasonable to expect from them and what's not reasonable i.e. what is static, what is dynamic, if there are artifacts how do they get created, what if the data schema is dirty...
some of these questions I can answer myself just playing around with them, but I think I'd have to be comfortable implementing them before being comfortable using them.
some of these questions I can answer myself just playing around with them, but I think I'd have to be comfortable implementing them before being comfortable using them.