"Building analogue quantum devices that can simulate the behaviour of other quantum systems more efficiently than any classical apparatus is deemed possible and highly desirable. Such advances will give immense boosts to a variety of fields, from nano-devices to quantum chemistry and information technology. A major current roadblock to this end is the fact that special-purpose quantum simulators have no known mechanisms of self-stabilisation or validation protocols; while it is perfectly known that errors are unavoidable in any experimental setting and even that many of the target systems of interest possess regimes of extreme sensitivity against perturbations. Furthermore, our current understanding of the effects of imperfections on real-world quantum simulators is remarkably poor. The latter is precisely the main reason why it is still not known whether quantum simulators will actually be more powerful than conventional computers at simulating quantum-mechanical systems. Reliable Quantum Simulators (REQS) will contribute to answer this question. In a first stage we plan to derive scaling laws with the system size for the behaviour of generic quantum simulators under realistic noisy conditions. We will then develop interactive protocols to validate the outcomes of realistic noisy simulations. In a final stage, we plan to gain insight on the true usefulness of real-world quantum simulators. This will include obtaining formal evidence on whether or not the latter are hard to simulate for classical computers. Ultimately, the breakthrough character of REQS lies at directly challenging a current common view that sustains that quantum simulators are intrinsically so robust that they do not require validation or error correction. That is, REQS will address the uncomfortable question that quantum simulators could be unreliable, or, equally bad, reliable only in the trivial regimes."