They show up within a day or two whenever we’ve noticed an uptick in creepy crawly of critter activity. Most recently we had field mice show up from a nearby construction lot. The mice attracted a massive diamond back onto our porch! We also saw our first scorpion. They showed up today, two days after I called, and sprayed the inside and out, set up a snake repellant parameter, and laid down some mouse stations. In mid September we had an influx of black crickets all around our house and noticeable uptick of spider activity. They came by in two days and sprayed inside and out. Both the cricket and spider sightings fell dramatically!