Rule of 80
Refers to a vesting requirement by TRS to qualify for certain retirement benefits. \'80\' equals the total of the number of service credits (years of service) under TRS plus current age. This can be any combination (e.g. 25 years of service at 55 years old or 30 years of service at 50 years old). Other benefits may have different vesting requirements (Rule of 70 or Rule of 90), but the concept is the same.