Good flock management is integral to sheep farming. An important aspect of this is optimising ewe lifetime production by reducing wastage (premature culling and ewe mortality). The consequences of reduced lifetime production include financial and environmental impacts, poor flock welfare, and, damage to the reputation of the industry. This chapter begins by defining ewe wastage and summarising what happens on sheep farms globally. We compare this with industry targets and discuss technology that can be used to gather information. We briefly look at common diseases that affect ewe longevity. This leads into a section on ewe nutritional requirements and how to assess ewe condition, with a major focus on ewe body condition score (BCS) at key production points (mating, scanning, lambing, 8-weeks post-lambing and weaning). We finish with a case study summarising how data collection and analysis, using the electronic tagging technology, has a positive impact on flock production.