I am always amazed at the sketchbooks of American artists and students. They are told in school how these little books are what keeps them current. This is the place where you experiment and look for things, this is where future approaches and techniques are found first. And they are not lying, actually they are pretty damn right. But don't feel bad if does not work for you, you are not alone there. It is your book and only you decide what you do with it.
My sketchbooks are an exploration tool but not really of my work but the way I look at the world.
Outside of the studio is where I find inspiration while still take a break from work.
I use a pentel brush and a water brush, tools I don't use in my illustration work for getting out of the commodity of your usual pick which in my case is a pencil. Yet still carrying those two things plus a small notebook is never a problem since I don't like carrying around many tools and boxes (well I actually do but my back does not) so you can always be ready.
I draw from life, from pictures and from my head so hopefully one day the result of those different inputs does not differe all that much.
There is no pressure in these drawings just fun.
Thanks for looking