Key changes to 401(k) plans are set for 2025, including an increase in employee deferral limits to $23,500 and a new catch-up contribution limit of $11,250 for workers aged 60 to 63. Additionally, part-time workers will gain easier access to retirement plans, and most new plans will require automatic enrollment with a minimum 3% deferral rate. These updates aim to enhance retirement savings for American workers, particularly those who have struggled to save.