Honestly a smart watch has been a game changer for me simply for the timer function. I often don't walk around the house with my phone, so setting a timer either requires me to remember to set it once I'm back to it (and then the calculation of how long that took, which is an ordeal on its own) and then remembering to carry it around afterwards so the timer can do its job. But with a smart watch? It's right there, easy peasy to set and you can't put it down and forget about it. There's loads of other uses too, but easy access to timers is so handy