I will describe how I use mm-wavelength instruments (both spectrometers and photometers) to explore our universe across cosmic time. I will discuss instrument projects such as SPT, CMB-S4, TIME, and future even more powerful mm-wavelength spectrometers that will allow us to probe the universe, from the first fractions of a second after the big bang to the present day.  These new instruments and the detector technologies being developed can be used to study 1) inflation and neutrinos via the CMB; 2) the epoch of reionization; and 3) galaxies at the peak of star formation.  I will also provide updates from the currently ongoing field deployment of TIME at a 12m telescope at the Arizona Radio Observatory.