Build quality is often overlooked, but it's a make-or-break factor for repeat business. A disposable that leaks or dies early becomes a headache for you and your customer. Look for devices with solid construction—a snug mouthpiece, a sealed battery compartment, and a weight that feels substantial.

For example, the LINQ-PRO has a reputation for a robust build, which translates to fewer complaints. On the other hand, some cheaper alternatives might save you a few cents per unit but cost you in returns and lost trust.