retirement planning mistakes, underestimating retirement costs, saving not enough for retirement, retiring too early, neglecting healthcare costs, ignoring inflation, overlooking Social Security options, failing to diversify investments, not maximizing employer contributions, withdrawing from retirement accounts too early, forgetting about taxes in retirement, not having a retirement plan, relying solely on Social Security, carrying debt into retirement, not considering housing costs, neglecting long-term care planning, overlooking risk tolerance, ignoring estate planning, failing to adjust spending habits, not reviewing retirement plan regularly