If you're an online-only shopper, buying in bulk is tempting—it saves money and saves trips. But here's the trade-off: devices sit in warehouses longer, and heat during shipping can degrade the e-liquid. The nicotine can also oxidize over time, giving it a peppery taste. Before you stock up, check the production date if it's listed. Buy from reputable sites that rotate stock. And when you get your order, let the devices acclimate to room temperature before opening—especially if they've been sitting in a warm delivery truck.