5% is not typical. The highest strength vape juice sold in most places is around 24mg/mL or 2.4%. Most "old-school" vape users smoke something more like 12mg.
You realize quickly that the Nicotine content isn't super important as long as you taper it down.
Which is not an option with Juuls and the other disposable garbage products. Refillable Vladdin style devices are the way to go.