I used that yellow Pickett slide rule from junior high school through my EE degree at MIT. It was a yellow Pickett model N4 (
http://www.sliderule.ca/pickett.htm).
The slide rule was a wonderful thing for me. I got the idea that I would like having one from the book Have Spacesuit--Will Travel, by Robert Heinlein, a book I read when I was around twelve. The paper route a couple of years later gave me enough money that I could buy one.
Growing up in the 1950s and 60s, there were no computers used in everyday life. The slide rule was the only practical way to perform calculations quickly, sadly to only 3 significant digits. An important skill taught in High School back then was using tables of logarithms and trig functions to perform calculations (with this approach one can easily get 5 significant digits of accuracy). I still have my CRC handbook of Mathematics that I bought for myself in High School, I learned a lot by studying each formula and each kind of reference table in that book.
I taught myself to program from a book on Fortran in 1967. I was able to submit programs punched on cards to a friend who would run the program on the School district's single computer used in their administration building. A couple of days later I would get my listing back!
Like the TI Calculators today, slide rules were ubiquitous in my engineering classes. Although I went to college in 1969, I've taken classes at the local University as recently as ten years ago for fun. I brushed up on my long unused differential equations and learned some new things, a Graduate course on Combinatorics.
It's very interesting to see the difference between my approach to working through problems and the methods used by other students in my differential equations class. They would almost invariably reach for the calculator to work through a complex expression, entering each term and finally coming up with the answer. By habit, I normally simplify, factor and reduce the complex expressions before doing any arithmetic. The younger students are masters of the calculator; I'm not very fast with a calculator. I just never had access to a calculator while in school and never gained the proficiency of today's typical college students.
I've got an advanced TI calculator sitting in a drawer (and the old slide rule stashed somewhere in the house), but I never really use it. If I need to do some quick calculation my preferred method is to simply fire up the Python REPL in a terminal window.