In the first half of this talk I will show how several properties of the QCD axion can be extracted at high precision by combining NLO chiral perturbation theory computations with recent Lattice results. I will also discuss the unreliability of conventional instanton approaches at finite temperature and study the impact on dark matter and cosmology. In the second half, I will describe a deformation of the recently proposed relaxion solution to the Electroweak hierarchy problem. By considering models where the relaxion has a temperature dependent potential I will show it is possible for the mechanism to work without the very long period of inflation that is required in the original versions.