Dual-comb molecular and pump-probe spectroscopy with equivalent time sampling are currently limited by the cost, complexity, and size of conventional optical comb systems, based on two modelocked lasers and corresponding feedback loops. The single-cavity dual-comb diode-pumped solid-state and semiconductor lasers, however, substantially reduce the complexity of existing systems to a single compact free-running laser. In comparison to other competing new approaches such as quantum cascade lasers or micro resonator combs, these dual-comb lasers provide substantially more power per comb line with low linewidth and noise, and are ideally suited for a 40 MHz to 5 GHz comb spacing. The optimal operating regime lies within this range for many different applications including spectroscopy and thin-film inspection, allowing for fast, accurate, and sensitive measurements.