Limited memory capacity is one of the major constraints in delay tolerant wireless sensor networks. Efficient management of this limited resource is critical to the performance of the network. This paper proposes a novel buffer management algorithm, SmartGap, that contrary to most other algorithms does not consider the priority of packets in isolation. Instead, SmartGap is a so-called Quality of Information (QoI) focused buffer management algorithm. That is, in a wireless sensor network that continuously measures some parameter, the value of a single packet is governed by an estimation of its importance in the reconstruction of the sampled signal. Attractive features of SmartGap include a focus on QoI, low computational complexity and simplified reconstruction of the original signal. Simulations in which the performance of SmartGap is compared with the performance of several commonly used buffer management algorithms in wireless sensor networks are provided in the paper. The outcome of these simulations suggest that SmartGap frequently provides improved QoI compared the other simulated algorithms, and upholds fairness between competing data flows.