As a gamer, what has typically worked for me is to upgrade the video card every two years, and only other components if they are the system's bottleneck. Every four to six years, the motherboard, CPU, and RAM are upgraded. The PSU and case both get upgraded very infrequently. only when there has been a significant advancement in technology (e.g. jump from CRT to LCD, jump from 1080p to 2K and HDR, etc.) SSD only when required.