In these of unleaded fuel, you may use spark plugs until the electrode erodes away. Every-so-often, check the center electrode for a sharp edge. As slowly rounds off, file it sharp.
Admissions officers look first at test scores, the rigor of the courses you take, and your grades in those courses. After that, they are interested in a student's extracurricular activities -- in other words, how you spend your time outside of classes.
This is because the University of Colorado has holistic admissions. CU takes into consideration the rigor of your high school courses, your application essays, and your extracurricular activities. Student also have the option of sending letters of recommendation. Applicants to the College of Music need to audition.