Sediment accumulation rates are a powerful tool for interpreting the rock record, offering insight into the depositional environment of a given locality and the (in)completeness of a given stratigraphic record. Classic approaches to sediment accumulation rate characterization required large data compilations, but the advent of high-resolution age models enables the use of individual sections and regional composite records to generate a large enough sample size of accumulation rates to estimate stratigraphic completeness. Because of these prior limitations, it is unclear how precisely accumulation rates are known for many stratigraphic sections, with rare and discrete horizon-horizon accumulation rates potentially biasing results. Here, I explore how to leverage high-resolution age-depth models to reveal accumulation rate-duration trends for individual sections and to better understand depositional histories by calculating accumulation rates for every horizon in a given section. First, I demonstrate these analyses on three synthetic age-depth models. I then examine regional composite carbon isotope records from the Ediacaran to test the effectiveness of my method on real data. Based on the accumulation rate–duration relationship, I estimate that the Ediacaran Oman and China stratigraphies are ~22% and ~37% complete at a 1-Myr interval, respectively. I find that accumulation rates drop following the Gaskiers glaciation and are relatively low during the Shuram carbon isotope excursion. Furthermore, the Oman carbon isotope stratigraphy demonstrates increasing accumulation rates across the Ediacaran, peaking near the Ediacaran–Cambrian boundary. Using an iterative technique, I estimate mean accumulation rates and durations, with uncertainty, and demonstrate how iterative-style Sadler plots can be used to interrogate depositional histories. In an effort to facilitate this approach and further quantitative developments across the stratigraphy community, I provide an open-source function that generates the plots herein for any stratigraphic record with an accompanying age-depth model.