I'm fine with SPs. I buy them just like I buy GPs and EPs. I certainly don't expect as much since they are only $10. However, I don't usually buy them right away unlike some GPs. EPs are about the only packs I've bought immediately upon release with the exception of the times I wasn't currently playing TS4. I have other games I enjoy other than TS4 and can get wrapped up in them instead. I currently own all the packs and it has been my choice to purchase them all of them.
I would like to add that Laundry Day SP actually, to my count has 5 gameplay items (washtub, clothes line, hamper and the washer and dryer) with the washer and dryer having the same animation.
Yes, they add up and that's the part that's getting old for me. The whole shabang is expensive -- more expensive than any other game I've played.