The measuring of time is important for a great number of purposes, and is universal in its importance. The methods used to measure it are far less universal, however.

Many species base their basic units of measurment of the rotation and orbit of their homeworld, while these are logical units on that homeworld, they become highly arbitrary and often unwieldy when used anywhere else. However, using a different set of time units on every world quickly makes interstellar communication and recordkeeping even more unwieldy.

The most commom solution to this problem is the use of two or more parralel measuring systems, one based on local time, and the other(s) on some version of 'universal time' used over a large area. An example of such a universal time is Terran Time, which uses Earth timekeeping as a reference point.

Universal timekeeping is not as simple as simply converting local time and dates into their universal equivilant however. The flow of time is slightly different in different areas due to relativity, causing slow but accumalating inaccuracies. Sometimes it is difficult to even accurately determine when 'now' is in relation to universal time, as a ship in FTL transit does not experience time. Due to the various methods of calibration used, and the accumalation of errors, systems could be several decades out of synch with each other. As a rule of thumb, the further from sol, the greater the likelyhood of local timekeeping being significantly out of synch with the timekeeping in nearby systems.