My fancy electric toothbrush does it for me. It hesitates slightly every 30 seconds. You are supposed to brush one quadrant for 30 seconds. That’s outside lower left. Then inside lower left. Outside upper left. Inside upper left. So that is two minutes on the left and two minutes on the right. That’s a long time. And the brush lights up if you push too hard.
I was reading a review of the brush. Some guy, who apparently knew so much that he didn’t read the directions in the piece of paper that came with his expensive brush, complained loudly that something was wrong with the dang thing. He said it was no good 'cause it kept stopping and starting every so often. Well…duh?
Now if you don’t brush or floss then the time it will take to brush whatever teeth you have left will become progressively shorter as you age.
So brush (and floss) only the ones you want to keep.
I used to use this podcast called “Chompers” when brushing with my kids. It’s actually a pretty good way to handle it, just distracting enough so you can still do the task without the boredom setting in.