Used to move verts one by one, then found out about the loop cut tool 3 weeks in
For my first two models I dragged every single vertex around by hand and it took me like 4 hours to do a simple mug handle. Then a guy in a Discord server said 'just use Ctrl+R' and it literally took 30 seconds to add clean edge loops on my third try. Now I feel kind of silly but also curious, what early tool did you find way later than you should have?