Sometimes I only need one portion for a pot of soup, or a recipe wants some weird percentage of a package. Sometimes that works out between cooking sessions (the weird percentage left over is just enough for the soup!), but I generally can’t be bothered to stockpile odds and ends of pasta in the hope it works out. Easier (and more fun, imo) to just put two kinds in the same dish.

Fair!

Not OP, but if I only have a little bit left of one package, it makes sense to use it up and round out the required amount with a new package, which might not be the same shape or brand (and times vary widely between brands sometimes, too). I mean, I’m probably not throwing elbows and spaghetti in the same pot, but elbows and shells, or two different brands of elbows for some nice mac & cheese? Absolutely.