Six months is use and still runs brilliant. Does require some weeks of practice to develop technique. A tank lasts for about 30 seconds and to refill tank takes five seconds. I use 2 or 3 tanks morning and mid-day and 4 or 5 tanks at bedtime for a total of 5 or 6 minutes use per day. Recharging overnight every 2nd day. Has noticeably more blast when fresh charged. Inside can develop a stale smell and therefore I now recharge with the tank removed. This product cleans teeth so well it can almost replace brushing .. although I still use a brush to distribute Pro-Relief toothpaste. I’ve been a daily user of floss/tape for more than 30 years and still use tape once a week to see if the water cleaner has missed anything .. it doesn’t. So a huge thank you to Mr Panasonic for bringing us such an excellent dental cleaner and thanks to Mr Norman for making this product available at a reasonable price.