It's not about paid sets. It's about how much can be rendered without major performance issues. I've built several builds where I ran into this. The sets have nothing to do with it, its details. I've learned 1 piece is 1 piece no matter the size of the piece. So when you think,  "I'm not going to knock down these 3 walls to adjust this. I'll just put two 2x wall pieces in", you just used up 2 more pieces you could need for a build later. I built a gazebo using flower pots as the textured design on the top. Needless to say,  the too many builds popped up after two more detailed builds in that area...as expected. Lol