Don't ignore the spread on stablecoin on-ramps.

Biggest mistake I've made recently was underestimating the impact of the bid/ask spread on stablecoin on-ramps when converting larger fiat sums. You look at the spot price for $USDC and think you're good, but that 50 bps spread on a high-volume conversion can eat into your effective capital fast if you're not paying attention to the actual execution price. Lesson learned: always account for transaction costs beyond just the fee percentage.