As time goes on, your R scripts are probably getting longer and more complicated, right? Timing parts of your script could save you precious time when re-running code over and over again. Today I’m going to go through the 4 main functions for doing so. Nested timings 1) Sys.time() Sys.time() takes a “snap-shot” of the current time and so it can be used to record start and end times of code.