With different people recommending different amounts of perlite in carnivorous plant soil mixes, the guys at Sarracenia Northwest decided to take the scientific approach. They tested mixes ranging from none to 60%, in 10% increments. Their results showed that 40-50% perlite is optimal for drainage and aeration. A real eye-opener is at the 11:55 mark where Jacob says "We have a large pot of flytraps that have been in the same soil for the past 8 years." That is truly amazing. I usually have to swap out my flytrap soil after 2 years (3 is pushing it).
In light of this, I'm adjusting my soil mix. I had been doing a 3:1:1 ratio of peat moss, perlite, and sand. I'm changing that to 4:3:1 to get more perlite in the soil. I'm not ready to give up the sand just yet.