Retirement readiness hinges on three critical numbers that every worker should know before leaving their job. First, your investment account balance determines how much supplemental income you'll have beyond Social Security. Experts recommend withdrawing 3.7% of your total retirement savings in your first year of retirement to maintain financial stability.

Second, understanding your Social Security benefit is essential since it provides guaranteed lifetime income with inflation protection. The average benefit replaces about 40% of pre-retirement earnings, though this varies based on your lifetime earnings and when you claim benefits. Those who delay claiming past their full retirement age receive increased payments through delayed retirement credits.

Finally, calculating your annual expenditures ensures your combined income from savings and Social Security covers all retirement expenses. Financial planners typically recommend planning for expenses that replace about 80% of your working income, including healthcare costs. By determining these three numbers - your investment balance, Social Security benefit, and annual spending needs - you can make informed decisions about retirement timing and avoid the common mistake of leaving work too soon with insufficient resources.