The Hydro Floss regular jet tips are designed to be changed approximately once every 90 days.
The problem is that the tips often do touch our teeth even though we are not aware of it.
Over time, this can change the diameter of the hole in the end where the water shoots out.
This could alter the way the device works.
You can visually inspect your tips to see if they are wearing down at all.
However, the manufacturer does recommend that you change the tips every 90 days.