The Internet of Things (IoT) brings a paradigm where humans and “things” are connected. Reliability of these devices becomes extremely critical. Circuit aging has become a limiting factor in technology scaling and a significant challenge in designing IoT systems for reliability-critical applications. As IoT becomes a general-purpose technology which starts to adapt to the advanced process nodes, it is necessary to understand how and on what level aging affects different categories of IoT applications. Since aging is highly dependent on operating conditions and switching activities, this paper classifies the IoT applications based on the aging-related metrics and studies aging using the foundry-provided FinFET aging models. We show that for many IoT applications, aging will indeed add to the already tight design margin. As the expected chip lifetime in IoT devices becomes much longer and the failure tolerant requirements of these applications become much more strict, we conclude that aging needs to be considered in the full design cycle and the IoT lifetime estimation needs to incorporate aging as an important factor. We also present application-specific solutions to mitigate circuit aging in IoT systems.