The paint stick is my favourite bookcase shim, Stilly. My library/music room contains seven bookcases, all but one shimmed with a paint stick (the four-litre length) in the middle of the front bottom edge. I'm not sure it's possible to keep house without a basket of shims and a bouquet of paint sticks.

I can't imagine housing and maintaining so much legacy computer hardware, but then I'm not only a neat freak but also allergic to extra anything except, perhaps, Wedgwood bone china. Instead of several printers, I have a plethora of coffee cups and no fewer than six teapots.