I have a longer analytic expression in several variables containing special functions and others. Does Mathematica bring tools - or are there any packages - to examine the stability when I evaluate the expression numerically. I want to understand for which variables the accuracy of the numerical result is lowest in order to see how I can rewrite the expression to improve the result at finite precision. Note that the goal is not to obtain a high accuracy result by telling Mathematica to use more digits. I rather want to have an expression which evaluates accurately using a relatively small number of digits. Since it is not obvious how to achieve this because of the length of the expression I would like to have some help from Mathematica telling me how to optimize the expression.