I wait for good sales and buy several cartridges when I can, between sales I stalk. I review the gypsy, cricut.com, and fellow bloggers to see what the images look like. I don't use "the cricut craftroom" or "design studio" programs. When I get a new cartridge: I rip out the extra languages pages; read through the handbook, note how many blank or missing images are on the cartridge on the package. When I remember I put a sticky note with ideas that occur to me as I review the handbook. Then I have to register the cartridges, and claim the points certificates. It is great not to do the registration immediately, sometimes there's a double points promotion. Finally, points that add up to something useful, I think I have cashed in points for at least 8 free cartridges from cricutrewards.com!
Now, here is the shocking part. I use as much scrap papers as I can. If I have to do exact measurements or locations, I will write it down exactly where the blade location is for reference. I don't need to be that fussy for test cuts. The cricut usually knows where I have already cut something on the mat and that will sometimes make it squawk and beep that there's not enough space or some nonsense with its invisible image margins. The trick is to hit "clear display" or unload & re-load if its being a pain. Having the "Paper saving" button on all the time helps too. I'll admit, guess-timating with scraps sometimes wastes a paper if the blade goes over or the image is oriented in a surprising direction. It doesn't happen enough to make me stop using scraps!
I lay down the next colour close by the first cut, move the blade back, pick the layer and cut. Shift + base image button 18 out of grey. See some of the cuts come up with the paper? No biggie, leave them as they are, but cut away the excess paper and leave it as a chunk on the mat.
Once its all off the mat & I'm done with marathon cutting I use a non-fragrance, non-alcohol baby wipe to wipe off the mat of little linty paper bits. The tiny bit of moisture it imparts seems to help re-sticky the mat a bit longer.
Here's what I've been up to. Don't ask me which cartridges the images came from, I didn't take any notes. The papers are from my stash. Some of the cuts are 2" just to use up the paper.
Bambi was cut at 4" and I didn't think she was much fun to create that small.