In vJASS we usually use timer systems because they are the easiest to deal with. You can also do indexing, but with timer systems you have that ease of modification and it is overall a lot easier to understand.
To learn more about timers and vJASS, I highly recommend this tutorial:
http://www.thehelper.net/forums/show...Timers-in-JASS
It is a bit outdated because it doesn't have CTL and that jazz, but those systems all work 100% and are still used in several systems created today.