Being complex systems containing vast amounts of gas, dust, and stars, galaxies allow us to study the Universe in great detail. It is inside these systems that stars form, and transform the simplest of elements, hydrogen, into heavy elements essential for life as we know it. Precise metallicities and chemical abundances of the different components in galaxies are critical for understanding galaxy formation, feedback and interstellar/intergalactic chemical enrichment. I will present results from our metallicity studies of nearby galaxies with a dedicated focus on their neutral-gas, ionized-gas, and stellar components. Using spectroscopic observations of star clusters covering a broad range of ages (~2 Myr to ~12 Gyr) we probe the chemical enrichment history of the host galaxy. I will discuss recent work exploiting spectroscopic observations acquired with the ESO Very Large Telescope and the Hubble Space Telescope where we proved that detailed abundance and metallicity analyses are possible using star clusters at distances of several Mpc. Such studies involving stellar populations of different ages allow us to observe the chemical evolution of galaxies through a much larger window in both space and time.