Downloadable computer application software for smart phones and other smart devices, namely, software for use in: alerting one leaving a location or another that the one may have forgotten to take with him an item; alerting, via a smart phone or other smart device, one leaving a location or another that the one may have forgotten to take with him an item to which an item-tracking device is attached; alerting one, via a smart phone or other smart device, that a separation between a smart phone or other smart device and an item to which an item-tracking device is attached has been greater than at least a threshold distance for at least a threshold period of time; alerting, via a smart phone or other smart device, one leaving a location or another that the one may have forgotten to take with him an item-tracking device; alerting, via a smart phone or other smart device, one leaving a location or another that the one may have forgotten to take with him an item that incorporates a tracking device or that is otherwise trackable; alerting one, via a smart phone or other smart device, that a separation between a smart phone or other smart device and an item that incorporates a tracking device or that is otherwise trackable has been greater than at least a threshold distance for at least a threshold period of time; generating, with a smart phone or other smart device, a visual, audible, haptic, or other sensory alert that one leaving a location may have forgotten to take with him an item to which an item-tracking device is attached; generating, with a smart phone or other smart device, a visual, audible, haptic, or other sensory alert that a separation between a smart phone or other smart device and an item to which an item-tracking device is attached has been greater than at least a threshold distance for at least a threshold period of time; generating, with a smart phone or other smart device, a visual, audible, haptic, or other sensory alert that one leaving a location may have forgotten to take with him an item-tracking device; generating, with a smart phone or other smart device, a visual, audible, haptic, or other sensory alert that one leaving a location may have forgotten to take with him an item that incorporates a tracking device or that is otherwise trackable; and generating, with a smart phone or other smart device, a visual, audible, haptic, or other sensory alert that a separation between a smart phone or other smart device and an item that incorporates a tracking device or that is otherwise trackable has been greater than at least a threshold distance for at least a threshold period of time