1st Place: In 2006 I bought the 7800GT 256MB for $295. This was the most I had spent on any computer part ever. I replaced it 2 years later with an 8800GT for $212, which I still consider my best GPU purchase, followed closely by my GTX 1070..
2nd Place: I wasn't going topend, but I bought a $150 GTX 460 768MB and it was terrible. Replaced it 2 years later with a $250 Radeon 7870XT 2GB. The 7870 was a good card and the only game that gave me VRAM problems was Arkham Knight.
Despite many reassurances that 8GB on the 3070 is fine, especially with DLSS and and a target of 1440p, I still am a bit hesitant. My 1070 was the closest to launch I have ever bought a GPU and I waited for a few months, so I could get a decent AIB for $430. I figure if I wait the same amount of time, I can be a little more confident by then.
Nothing feels worse than spending a bunch of money on something, only to have it "replaced" in short order. Looking at Radeon VII and the GTX 2070 in particular. The 5700XT and the GTX 2070 Super cards came to soon and made the original 2070 seem like a stopgap. Radeon VII is even worse.