Mobile Rapid-DNA devices have recently become available on the market. These devices can perform DNA analyses within 90 min with an easy ‘sample in–answer out’ system, with the option of performing comparisons with a DNA database or reference profile. However, these fast mobile systems cannot yet compete with the sensitivity of the standard laboratory analysis. For the future this implies that Scene of Crime Officers (SoCOs) need to decide on whether to analyse a crime sample with a Rapid-DNA device and to get results within 2 h or to secure and analyse the sample at the laboratory with a much longer throughput time but with higher sensitivity. This study provides SoCOs with evidence-based information on DNA success rates, which can improve their decisions at the crime scene on whether or not to use a Rapid-DNA device. Crime samples with a high success rate in the laboratory will also have the highest potential for Rapid-DNA analysis. These include samples from e.g. headwear, cigarette ends, articles of clothing, bloodstains, and drinking items.