In the hours following the 2020 COVID-19 outbreak and subsequent shutdown, educators across the nation were suddenly tasked with teaching online. As Jen Vanek describes in "Supporting Quality Instruction: Building Teacher Capacity as Instructional Designers (Part 1 of 3)" (EJ1344704), the majority of educators had to quickly learn and adopt new ways of planning and delivering instruction. Over time, the conversation around the role of technology in adult education shifted. In spite of the tremendous hardship experienced in and outside of the classroom, the crisis revealed an untapped opportunity to meet the needs of adult learners more effectively through flexible programming, digital skills development, and personalization of learning. The purpose of this article is to delve deeper into the myriad individual and systemic factors that impact the adult learner, educator, and their interactions through the lens of learner variability. Embracing well-designed and implemented education technology is a major step in the future of equitable and sustainable learning for adult education, and understanding the whole person remains at the core of learner success. [For Part 2, see EJ1344707.]