For one build I made that mistake. I went with SFF partly due to motherboard and RAM shortages and i could barely upgrade it... I won’t do that again. But before that i would start at low to mid spec for components, a mobo and PSU with room to grow, and slowly max them out over time.

However, like i said in another reply it seems like i can repurpose less and less in later builds as tech evolves more rapidly these days and or I run into a wall with bottlenecking something or another even if i can upgrade a component. As a result I’m definitely taking a longer pause this time.