Call as much as you can without passing out. I vary it up when by myself. I will call short series 30-90 seconds with short 15-30 second breaks, and then call long series 90-300 seconds with 1-2 minute breaks. In all seriousness, if you are not buddy hunting then electronics is probably the way to go, but I am too much of a cheap ass to spend the money for a good e-caller.