The dependability evaluation and management of complex systems is often based on the collection of field data from event logs. Nevertheless, key decisions about log production and management are usually left to the late stages of development, leading to heterogeneous, inaccurate, and redundant logs. This in turn decreases the level of trust on logs. This paper proposes to enrich traditional logging by defining a set of rules, to be followed at design time, specifically conceived to improve the quality of logged failure data and to ease the coalescence of redundant or equivalent data. A tool for processing our rule-based logs has been developed to show the feasibility of the approach. The tool is applied on a real-world case study in order to evaluate the effectiveness of the approach when compared with traditional logging.