I bought a large assortment of sand timers to use instead of my phone, because although I believe my brain is resting when I'm looking at cartoons or saying hi to my friends, my problem is that I'll stretch out the break longer than I really want and get less work done during the time I've set aside.
Today, I'm going to use the five-minute timer to shift between pieces, and the 10 second timer to use between sets. I might buy a metronome and a wooden abacus to track repetitions and exile the phone altogether. I don't like counting in my head or out loud. I like watching the sand move in the little timer. I enjoy handling the physical objects too. Piano is like a really fascinating puzzle, and practice is like a game.
What I do while the sand runs in the 10 second timer is focus on physically relaxing because I have a lot of tension, so everything works nicely together.