We have established mid-infrared hydrogen recombination lines observed with JWST as accretion tracers for pre-main-sequence stars that accrete from circumstellar disks. These new relations equip the community with a direct measurement of the accretion luminosity from MIRI-MRS spectra. A MIRI-derived accretion luminosity is fundamental for time-domain chemistry studies, as well as for studies of accretion in embedded/distant sources that are currently inaccessible in the optical. Our work was made possible with a coordinated, multi-observatory effort that monitored the well-known binary system DQ Tau over three orbital periods, capturing its periodic accretion bursts. In this talk, I will present 9 epochs of MIRI-MRS spectra that were accompanied by near-simultaneous LCO photometry and VLT X-Shooter spectroscopy. This program caught exceptional accretion variability, spanning almost two orders of magnitude between the peak of the first periastron accretion burst and the following quiescent phases. The MIRI spectra show H I line luminosities that vary in step with the ground-based accretion-luminosity time series. The tight correlation with accretion and the large line widths, which MIRI resolves for the first time, support an accretion-flow origin for mid-infrared H I transitions. Combining these three exceptional datasets, we derive accurate relations between mid-infrared line and accretion luminosities for three H I transitions (10-7, 7-6, 8-7), and improve upon a previous relation based on Spitzer spectra. These lines were selected because they are free from contamination by other molecular species (or can be easily corrected) and can be used without the need for a complicated thermo-chemical disk model. This ease of use and broad applicability make these accretion diagnostics an essential tool for any disk studied with the JWST MIRI-MRS.