Theories with large kinetic interactions have very relevant phenomenological applications in cosmology, in particular in the context of cosmic acceleration. Their Effective Field Theory (EFT) description relies on the so-called Vainshtein effect being operative. When incorporated at the quantum level, this mechanism ensures the validity of the theory in a non-trivial way. I will discuss how to estimate the regime of validity of such EFTs on the basis of computing the quantum corrections to the classical theory. I will point out how some lessons learned from the study of quantum effects in these theories might help us to tackle the significance of superluminalities and revisit what properties a healthy EFT should have.
