Should I use two 16GB sticks or four 8GB sticks for my PC?

Two 16GB sticks is the smarter choice. Four sticks put more stress on the memory controller, especially on consumer platforms like AM4 or LGA1700, making stability issues or trouble hitting rated speeds more likely. Two sticks just work and leave two slots open for an easy upgrade later. The only edge four sticks have is aesthetic or niche workloads that benefit from more ranks, but that’s rare and usually not worth the headache.