Understanding your 401(k) vesting schedule is crucial, especially when considering a job change. Your own contributions are immediately 100% vested, but employer contributions often follow a schedule. Cliff vesting means you own 0% until a specific date (e.g., three years), then instantly 100%. Graded vesting phases in ownership, such as 20% per year over five years. Leaving before fully vested means forfeiting unvested employer contributions. For example, leaving a job two months before a cliff vesting date could mean losing all employer contributions. Fifty-six percent of employers offering a match use vesting schedules, which can significantly reduce the effective value of the match for short-tenure employees. Financial Engines found that typical under-contributors forfeit $1,336 annually in matching dollars, which can compound to roughly $42,855 over 20 years or six figures over 40 years.

Choosing between a Traditional and Roth 401(k) depends on individual tax situations. Early-career workers in lower tax brackets often benefit more from Roth contributions, paying taxes now at a low rate and never again. High earners in peak tax brackets usually benefit more from Traditional 401(k)s, leveraging the immediate tax deduction. For those unsure, splitting contributions between both can offer flexibility in managing taxable income in retirement, particularly helpful for Medicare premiums and tax bracket management. Employer matching contributions typically go into the pre-tax bucket unless the plan specifically allows Roth employer contributions. Starting in 2026, higher earners must make catch-up contributions as Roth.

Annual fees significantly impact long-term savings. The ERISA Section 404(a)(5) disclosure, sent annually, details all investment options, expense ratios, and administrative fees. These disclosures reveal how well-priced a plan is; for instance, a fund with a 1% expense ratio is significantly more costly than an index fund with a 0.1% ratio. This difference can compound into hundreds of thousands of dollars over decades. For a $1.5 million portfolio, a 0.9% annual drag versus a 0.05% drag can rival a year's worth of contributions. Plan participants have legal standing to sue employers for excessive fees, as evidenced by over 120 class settlements totaling $665 million in ERISA excessive fee lawsuits since 2023. If plan fees exceed 1% of plan assets annually, it provides strong grounds to alert fiduciaries, who have a legal duty to monitor and minimize costs. Publicly available DOL Form 5500 also discloses total plan assets and service provider fees, searchable through the DOL's EFAST2 database, providing transparency on plan expenses.