The present chapter highlights the importance of the dynamical integrity theory for micro and nanoapplications. Three case-studies of devices at different scales are presented (a capacitive accelerometer, a microbeam-based micro-electromechanical system, and a single-walled slacked carbon nanotube) and different issues commonly addressed in the engineering design are examined via dynamical integrity concepts. The iso-integrity curves are observed to follow exactly the experimental data. They are able to detect the parameter range where each attractor can be reliably observed in practice and where, instead, becomes vulnerable. Also, they may be used to simulate and predict the expected dynamics under different (smaller or larger) experimental disturbances. While referring to particular case-studies, we show the relevance of the dynamical integrity analysis for the engineering design of a mechanical system, in order to operate it in safe conditions, according to the desired outcome and depending on the expected disturbances.