  The discovery of a truly habitable exoplanet would be one of the most
important events in the history of science. However, the nature and
distribution of habitable environments on exoplanets is currently
unconstrained. The exoplanet revolution teaches us to expect surprises. Thus,
versatile, capable observatories, and multiple observation techniques are
needed to study the full diversity of habitable environments. Here, we
summarize the challenges and opportunities of observing planets orbiting M
dwarf vs. FGK dwarfs, which are best targeted with different methods.
