Wireless sensor network research usually focuses on the reliable and efficient collection of data. Here, we address the next step in the traces lifetime: we aim at investigating and evaluating, by qualitative and quantitative means, data repositories of already collected measurements. We propose the use of a set of new metrics, which enable reliable evaluation of algorithms using traces (both in average cases and "stressful" setups) removing the need for running algorithms in a real testbed, at least in the development stage.