[First estimate of stellar populations in the Milky Way disk]
Sometimes creating your own population synthesis code from detailed (MESA) stellar evolution simulations is easier than updating old codes or learning new ones (that still are not able to create a trustable Milky Way population). I therefore developed an open source code that allows the user to create entire galactic (spiral or elliptical) populations from MESA simulations. From now the code only works for isolated stars, but the jump from isolated to binary grids is relatively simple!
It was also extremely useful in my Stellar Winds Atlas II paper to test different winds assumption in evolutionary models against Milky Way observations!
[First estimate of habitable exoplanets in an elliptical galaxy's disk]
My PhD wasn't about exoplanets. I had to use plenty of my private time, but after four years I managed to create my population synthesis code for habitable exoplanets. This combines my galactic population synthesis code StarEstate and the NASA catalogue of observed exoplanets to define planets' types (rocky planet, gas planet, water world, etc.), discriminate their habitability on the presence of liquid water, and extrapolate their number throughout the whole Milky Way. Still under development, but the first results are already here!