redgarl :
I prefer the scratch built option and waiting when everything align together. Buying parts in advance is usually not the best option.
I wasn't advocating "buying in advance" though. When I buy a new CPU+MoBo+RAM, I don't wait until I buy a new GPU, HDD, SSD, etc. months later (usually more like years for me), I put them to work right away because I actually need that part of my eventually fully refreshed system right away. If I buy a new PSU, I put it in right away. When I eventually upgrade the GPU, I put that in right away. Etc.
Balance? I consider that a largely pointless concept as there is no such thing as a perfectly balanced system unless all you ever do with your PC is run the only 2-3 games which may be optimal for any given CPU-RAM-GPU-resolution-details-etc. combination. One or the other is going to be the dominant bottleneck in all other cases and a GPU bottleneck can easily be loosened if not eliminated by reducing details to extend a GPU's useful life as needed. I see absolutely no need to tie CPU-MoBo-RAM upgrades to GPU upgrades and mine are 2-3 years out of cycle with each other.