Analytical performance evaluation is crucial in designing mobile multihop networks under different operational conditions. It provides the best insight into the effects of various network parameters and their interactions. The route and link lifetime in mobile multihop networks under a random mobility environment have significant effects on network performance. Many analytical studies have been introduced to the body of work concerned with the link and route lifetime in mobile multihop networks. However, there is no closed-form analytical study for link and route stability in MANETs under any random mobility model. In addition, to simplify the analysis, one or more network characteristics were not considered in most of related studies. This work presents a closed-form analytical model for the link and route lifetime in mobile multihop networks, where nodes move according to the random waypoint mobility model. The proposed model can capture the effects of most network characteristics including the number of mobile nodes, the number of hops, the network area size, the transmission range, and the speed of nodes. In addition, we used the proposed model to derive expressions for the bounds of the link and route lifetime under different network characteristics. The proposed model can help characterize the network performance, analyze the network as to meet a certain level of quality-of-service, and design better routing protocols to cope with link breakage caused by node mobility. To verify the proposed model, extensive simulations were performed under different network characteristics.