We analyze models that combine precautionary saving and liquidity constraints to provide a unified, more realistic treatment of intertemporal decisions. We start off with a simple three-period model to illustrate how the expectation of future borrowing constraints can induce precautionary saving even in scenarios in which marginal utility is linear. A more general model that allows liquidity constraints and precautionary saving to interact fully is the buffer stock model, of which there are two versions. One, developed by Deaton (1991), emphasizes the possibility that a prudent and impatient consumer may face credit constraints. The other, by Carroll (1997), features the same type of consumer but allows for the possibility of income falling to zero and so generating a natural borrowing constraint.