At high energies, high time resolution data is limited by statistics, with gamma-ray instruments like {\it Fermi}-LAT detecting fewer than a single photon per day for the average source. However, the time of arrival for each high-energy photon is known very accurately. This means that high-energy data can still be useful for sources with timing signatures, such as pulsars or galactic binaries. With it's all-sky observing strategy, the LAT also provides monitoring for sources with gamma-ray signals associated with flares or state transitions. Transitional pulsars are a prime example of these sorts of systems, as transitions between their low-mass X-ray binary and rotation-powered states appear to correlate with an offset in overall gamma-ray flux. Here we discuss the {\it Fermi} mission and instruments, the wide variety of gamma-ray sources, and details of the maximum likelihood analysis method. We also describe some recommendations for using gamma-ray data when investigating sources with time signatures that are singificantly shorter than the time separating individual gamma-ray events.