The structures of both intrinsic point defects in the neutral state -expected to be their preferred charge state in most samplesare indicative of low migration barriers along the c-direction, both involving only relatively small perturbations of the chain (an extra twist for Se i 0 , a longer bond for V Se 0* ) || which are expected to easily propagate along the chain with acoustic vibrations of the Se positions. This property, related to the low-dimensional crystal structure, may allow even lower intrinsic defect concentrations -particularly for vacancies -with sufficient mobilities to achieve equilibrium defect distributions at room temperature. The close relationships between bond distortions and defect energetics discussed here, and facile compressibility despite electronic sensitivity, indicate that strain could significantly affect defect behaviour in this system, potentially allowing its use as a materials engineering strategy for t-Se devices.