Another reason to CYCLE is that soil can only absorb so much water (intake rate). Both spray heads and rotor heads apply more water than soil can absorb. If you cycle your sprinklers for short run times, you allow the turf/soil combination to absorb more of the water you are applying.
Example- 5 zone system, 2 are spray zone, 3 are rotor zones.
Cycle 1 - starts at 3am, the sprays water 6 minutes each, the rotors 15
minutes each for a total of 57 minutes.
Cycle 2 - starts at 4am, the sprays water 6 min each, the rorors 15 min each
Cycle 3 - starts at 5am, the sprays water 6 min each, the rotors 15 min each
So, after the 3rd cycle is complete, you will have watered each spray zone 18 minutes and each rotor zone 45 minutes.
If your interested in more info read , "the complete irrigation workbook" by larry keesen.
I have applied this watering technique to every one of my irrigation customers. I have been able to save them water and provide a greener more drought resistant lawn. In the area I live, Colorado Springs, we have been allowed only 2 DAYS PER WEEK watering for the last 2 years do to drought conditions. I have had customers that watered everyday that were skepitical until they had no choice but to water only 2 days per week!