How the TRS pension actually works.

The formula, in plain terms

Most public school pension formulas come down to three things: how many years you've worked, your average salary over your highest-earning years, and a multiplier set by the pension system. Multiply those together and you get your annual benefit at full retirement.

The details vary by state and by which tier you fall under, which is why "years of service" and "final average salary" are the two numbers worth knowing cold — they matter more than almost anything else you'll do between now and retirement.

Retirement eligibility

Most systems use some version of the "Rule of 80" or "Rule of 90" — your age plus your years of service need to add up to a certain number before you can retire with full, unreduced benefits. Retire before you hit that number and your benefit is usually reduced permanently, not just delayed.

Common mistakes educators make

• Assuming their final salary alone determines their pension, instead of the average over their highest years.
• Not accounting for how a late-career raise, or lack of one, changes the final average.
• Retiring one or two years before hitting full eligibility without realizing the reduction is permanent.
• Not knowing how their pension interacts with Social Security if they've also worked outside education.
• Never running the actual numbers until the year they plan to retire, leaving no time to adjust.

Questions worth asking

• What tier am I in, and what rule determines my full retirement eligibility?
• What years count toward my "final average salary," and how is that calculated?
• What happens to my benefit if I retire one, three, or five years earlier than full eligibility?
• How does my pension interact with Social Security, if at all?
• Is there a survivor benefit option, and what does choosing it cost me monthly?