Neyman-Pearson based Null Hypothesis Significance Testing (NHST) belongs to one of the most commonly used methods in psychology. Carefully specifying and justifying the alpha (α) and beta (β) levels, which reflect the Type I and Type II error probabilities respectively, are crucial steps. As argued by Neyman and Pearson, these choices should depend on the context of the research at hand. However, clear guidelines for doing this are missing. As a result, the conventional level of α = .05 is often used as a default option and the consideration of β is often ignored. Importantly, the use of the conventional α-level is argued to be one of the leading causes of replication crisis. To address this problem, the goal of the current paper is therefore to propose an intuitive conditional justification of the error rates to guide applied researchers to choose a specific set of alpha and beta for each unique research scenario and to improve the credibility of research findings in psychology and related fields. More specifically, the selection of alpha and beta is based on (i) the proportion of true null hypotheses in the field of research and (ii) on the conditional probabilities of (in)correct conclusions given the decisions of the test. A Shiny app has been developed to help researchers to compute the new error rates. The presented method aims to encourage researchers to move away from conventional levels and, instead, strive to rationalize and customize their choices of alpha and beta for each research scenario. This shift aims to facilitate the attainment of credible and trustworthy conclusions, moving beyond automated decision-making based on conventional error rates.