Retirement is a transformative life event that exerts a substantial impact on the psychological, social, and behavioral well-being of individuals. This article conducts a comprehensive review of diverse theoretical frameworks, encompassing self-determination theory, life-span developmental frameworks, gerontology and aging theories, empowerment theory, social support and social exchange theories, alongside occupational psychology and organizational behavior theories. Utilizing a synthesis approach involving over 30 articles, we meticulously curated a selection of 10 articles closely aligned with retirement theories. This article critically dissects these foundational theories essential for understanding the nuances of retirement. It emphasizes the pivotal role of theoretical frameworks in molding research and shedding light on the multifaceted elements influencing retirement adaptation and overall well-being. These elements span psychological, social, emotional, physical, occupational, financial, relational, and community. In the conclusion, we delve into the implications of employing theoretical frameworks for future research that harmoniously integrates multiple theoretical perspectives. Furthermore, the article posits that these frameworks can serve as the cornerstone for designing effective interventions and programs aimed at aiding individuals in successfully navigating the intricate challenges of retirement transitions.

Thailand is facing a rapidly aging society, raising concerns about how retiring workers will maintain their quality of life. Insured persons in the social security system—especially voluntary members under Section 40 of the Social Security Act B.E. 2533 (1990), who are often informal workers—frequently lack formal retirement plans, underscoring the need for interventions that address financial security and subjective well-being (SWB) in later life. This study aimed to develop and evaluate a retirement planning program designed to enhance subjective well-being and improve the quality of life for pre-retirees in Songkhla Province. A Research and Development (R&D) design was employed in four phases. Phase 1 (R1) involved a needs assessment: survey data from 500 insured individuals (ages 40–60) were collected to identify gaps between current and desired retirement preparedness. Phase 2 (D1) utilized the needs assessment results and theoretical frameworks to design a Subjective Well-being Retirement Planning Program, encompassing financial, health, and psychosocial components. Content-relevance experts validated the draft program. Phase 3 (R2) involved implementing the program with 15 volunteer participants over four weekly workshops (each 3 h long) and evaluating its short-term pilot outcomes using pretest-posttest measures of subjective well-being. Phase 4 (D2) refined the program based on evaluation findings and expert feedback. Results indicated that following participation in the program, participants’ overall subjective well-being and all sub-dimensions (life satisfaction, positive and negative affect balance, sense of meaning, social connectedness, security, and health) were significantly higher than before (p < 0.001). Additionally, the proportion of participants classified as inadequately prepared for retirement (high-risk due to low planning) decreased markedly, suggesting increased readiness within the pilot group. Expert evaluations of the program design reflected a high content validity index and strong agreement on the program’s accuracy, appropriateness, and usefulness for the target group. In conclusion, the developed retirement planning program was associated with short-term improvements in subjective well-being and quality-of-life indicators among insured pre-retirees. This theory-informed program, developed through an R&D process, offers a model for supporting aging workers in the social security system, with implications for policymakers and practitioners seeking to promote healthy, happy, and secure retirements in an aging society.