Many routing algorithms, proposed for ad-hoc wireless networks, are based on source routing scheme. When a route is broken in source routing, route recovery and maintenance procedures are executed. However, these procedures consume many resources. To minimize route breaking, it?s important to find a route that endures longer time. Shortest path route has short lifetime especially in highly dense ad-hoc wireless networks, and it?s due to the edge effect discovered in this paper. Some routing protocols such as SSA [2] and ABR [3] are considering the link stability and try finding more stable route. In this paper, we will focus on the link stability and the lifetime of a route, and propose link stability comparison models for previously proposed routing algorithms. We will show properties of these models and compare them with local optimal algorithm that finds longest lifetime route at a given time. Finally, we will propose an enhanced link stability estimation model to find a route with longer lifetime.