I've changed! My mind at least. I've always been a huge fan of tools you can make from things you find around your house. And I still am. There are lots of items which make wonderful textures and cutting templates that hide under the cloak of the mundane. Toothpaste caps, baby spoons, asphalt, drinking glasses, milk pop tops... I could go on.
And although I still like the theory behind using real playing cards as spacers, and still recommend them for noobies - I've gone over to the commercially manufactured dark side. I bought some slats. And love them. The colors help me to find them on my messy bench, they're calibrated to card thicknesses so I can still use my favorite measuring method and they don't warp and get funky when I spill water all over them (which I am wont to do).
I was so proud of the way I used to modify my playing cards. Take your favorite suit - hearts for instance - and use double stick tape to add the correct amount of cards to the back of a numbered card to make a permanent stack. So to the back of a 3 of hearts I would tape 2 other cards making a stack of three. Then I'd wrap the stack with packing tape and cut down the middle. Voila! Two permanent stacks of 3 card thick spacers. I made 2, 3, 4 and 5 card stacks. If I ever needed higher spacers, I could stack two of my permanent spacers together. 5 and 2 make 7.
I made loads of these stacks to use in my class kits for students to borrow. And it works really well. Except they begin to get a bit shopworn and look shabby after a while. But not in a chic way. I'll still use my homemade spacers for students, but the slats I bought to try out for my personal class kit will now be joined by another set to use at home. I guess you can teach an old blue ribbon dog a new trick or two. Who'd a thunk!