For me, it’s an electric toothbrush. It doesn’t matter if you go with Sonicare or Oral-B, once you start using an electric toothbrush, regular toothbrushes don’t ever feel like they clean your teeth properly. The smooth plaque-free top layer of your teeth that you can feel after using an electric toothbrush can’t be replicated with a regular toothbrush.
I needed a Bluetooth speaker for my work PC (I work from home). I got one with a radio tuner as well. I’m fortunate that I have several radio stations in my area that play music I like. I prefer having some music on in the background while I work, but I was getting tired of having to actually think about what I wanted to listen to next. So I’ve been listening to OTA radio quite a bit, and it’s a nice change of pace from streaming music. And it’s not like the radio bits added much to the cost of the speaker.
Edit: also eyeglasses (sure, I’ll count that as a “gadget”). I hadn’t been to the eye doctor in probably 20 years. Hadn’t really noticed any problems but wanted to get my eyes checked since I had just gotten insurance. Doc recommended a prescription and now it’s like seeing the world in HD instead of standard def. If you’re in your late 30s/early 40s and haven’t gotten your eyes checked, it’s possible your vision has slowly degraded over time and eyeglasses will help more than you realize.