For software engineers, 59 is entry level (e.g. a college hire). Promotion to 61 (SWE 2) usually happens in 2-4 years of experience. Promotion to 63 (Senior) is usually 5-7 YoE. Promotion to 65 (Principal) is highly variable but a capable person who climbed the ladder all the way from 59 and didn’t get stuck with a crappy team/manager along the way would usually get there around 9-10 years, give or take.