are there guidelines of using Implicit enhancements?

Hi,

I am keen to find out if there are any guidelines around implementing implicit enhancements? Recently it has become easy to use implicit enhancement to provide a quick solution to a customer's problem. However i am not convinced that this is good solution and good to keep implementing implicit enhancements.

I would like to know what other consulting companies follow processes around these when it comes to implicit enhancement.

Thanks

RV