A multimeter is absolutely a good thing to have. Even for small electronics, you can do simple diagnosis like if a wire is broken, if an audio jack fucked, or even if a battery has any charge left.

I actually asked my dentist about water flossing lately and she told me that in her experience it’s not as effective at preventing plaque, and recommended regular flossing.

But for regular, the little brackets with floss already on them work great, much better than freehand thread.