Bliss and colleagues provide an account of an admirably large study of the cost-effectiveness of using different barrier products to prevent incontinence-associated skin damage (IAD) and demonstrate the time (and therefore the money) that nurses and carers consume when using such products. But incontinence-associated dermatitis is a conundrum in nursing practice. Difficulties with definition and, in particular, the confounding of pressure- associated erythema, have led to the reporting of widely varying prevalence rates. Similarly it has been difficult for researchers to identify a reliable and valid outcome measure for use in research. Therefore, whilst it has been possible for Bliss and co-researchers to demonstrate the different costs involved with different products, it has been much harder for researchers to demonstrate that any of the products work. Although many clinical trials of skin cleansing regimes and barrier products have been attempted, most studies of product efficacy in preventing IAD have been underpowered, have shown equivocal results, or have had methodological weaknesses (such as non-blinded rating of skin). There are also difficulties in determining which of the products may be effective: the cleanser, the barrier, or both combined. Studies have often combined the products together in a skin care "package." It follows then that although a skin cleansing/barrier product regime is widely recommended, this is based largely on expert opinion and there is a lack of robust studies to inform nursing practices for maintaining skin health. Bliss and colleagues show that application of skin barrier products is costly (with substantially different costs for different products), what is now needed is more evidence that application of these products is justified.