i have 8 sketchbooks in total spanning 5 years of design and the number will keep growing. Many people ask why i have so many and whats inside them and why i always carry one around. if your not a designer its difficult to understand or explain how important a sketchbook is and how vital it is to sketch ideas and record thoughts and inspiration. but my sketchbooks note every design idea and thought basically.
everyone thinks a sketchbook should be a portfolio of your drawing skills. to show off how talented you are but i treat them as amoungst other things a big notebook with drawn ideas. I have never been good at drawing, not bad but not brilliant and many people in my uni days thought you had to be an excellent artist to make it as a designer but that is very far from the truth.
Over the years i have got better at sketching and drawing due to the fact i carry a sketchbook with me and draw ideas, or joints or engineering principles for a design. I also write thoughts, quotes, designers to look up or websites to view. So it also acts as a diary in some respects. In terms of my career and passion for design, my sketchbooks are an importnat element. And for any budding designers out there i cannot stress how critical it is to record ever thought, idea or feeling, how ever varied, as it all helps to understand people, life and the world around you, and helps you better observe which to me is the most important part of design, bar none. so if you facny getting a sketchbook, get a good quality one. i use moleskine notebooks. heavyweight paper, small but not too small and stylish :) and get sketching, it will make you a better design through the years and improve your skills no end.