I've likely purchased 70% or more of the 52 Topps cards I've needed to help me complete my set.
I've obviously slowed down greatly since I only need 4 to complete my set but I still watch his auctions all the time looking for other cards that pique my interest.
https://www.youtube.com/watch?v=EcaFJEsRZfE
https://www.youtube.com/watch?v=jdH5oO8LU_A