My main computer is usually updated every 2/3 years (running a 5930k +64gb 3200 DDR4 right now), but the graphics and storage will at most be a gen back (currently running one EVGA 1080, up from a last gen Titan 😵 on a Crossover 404K 4K monitor. My fastest storage is a 500gb Samsung 950 NVME on top of a RAID0 with 4x 1tb Micron 600 SSDs and 2x 3tb Seagates in RAID1 (cold storage).
I think for me my money pit would be laptops ... I get hypnotized when I hear new laptops come out / specs. I just upgraded from my boat anchor Alienware 18 (4940mx 2x980m SLI, 500gb msata + 2x 1tb Samsung 840EVO RAID0) to a much more portable Asus GL502VS ... which I then promptly upgraded the 250gb PCIE m2 to a 500gb PCIE M2 and the 1tb spinner HD to a 1tb M600 SSD. The new 1070 gpu in the laptop is amazing, even compared to the 980 SLIs in the Alienware and the thin size / weight is crazy for just a 1 gen jump.