The concept of duration is different for everyone and we cannot judge what is expensive for you. We would like to show you that a VANN water bottle can be a unique investment with a high return. Imagine spending 40 euros on a reusable VANN bottle. This saves you on average 4 one-time bottles per month, which means approximately 10 euros per month. Over a year you will save 120 euros and have only spent 40 euros. This means you end up with a profit of 80 euros, which means a return of 200% .