Had to replace my old one because the handle assembly started leaking again. Twice now and I figured a new one would be better. The new unit is working fine right now but is louder than my older unit. Base was fine - but new handle assy leaked at the bottom of the main unit. The old handle started leaking inside the handle and I replaced it once. I would recommend this unit once or twice but after that I am going go buy the water flosser recommended and sold by my periodontist even though it is 40% more expensive.
I bought this a couple month ago because my Dentist told me I have Gingivitus and recommended this. It leaves my mouth feeling great and my gums are healthy again.
I used a Waterpik almost 40 years ago and didn't even consider it again until my dental hygienist told me she doesn't floss because she swears by her Waterpik and know I know what she means. It gets all areas between teeth and she is right, it does a much better job than flossing!