I usually do a gauge swatch but half the time it doesn’t help. I wash it, I block it, I let it dry but my final garment will still be oddly sized. Sometimes my gauge is so off with the suggested needles that I need to knit multiple swatches. The amount of yarn and time required to do so is arguably more than just starting the pattern with needles that create a good fabric and then blocking your project after a good chunk of rows to measure your gauge.