I use one on my phone Downloaded an app.
Also have the one I bought in 1980

I've been fairly happy with this one. Rechargeable, bright colored display. Headphone option although I've never used it.

ebay.com/itm/357241789730

I’ve been really happy with the Pro Metronome app. It’s free, has visual feedback for each beat, and is highly adjustable in terms of speed, time signature, and subdivision. I connect Bluetooth headphones and only pop one bud in. Works great.

The old wind up metronomes with the swing bar are I have always preferred. They give you the visual advantage of seeing and anticipating the beat, rather than just hearing it. The electronic metronomes only give you the beat. If you play the note when you hear the click, you are behind the beat. 

I’ve never found one that worked properly. Everyone I’ve tried slows down as I’m playing.

While I do like the mechanical, for the last three years I've been using a Korg KDM-3. Recently checking the price, it has more than doubled in cost since I bought mine, I wonder what caused that increase?

Nevertheless, it was the only digital metronome that sounds like a metronome and not a computer beeping torture device.

If you go mechanical, make sure you get one with a bell that rings the first beat of the measure. All the digital metronomes have this feature.

I do not recommend phone apps. In fact, I recommend you leave your phone in the other room when you practice.

I'd estimate that I use my Korg KDM-3 about 65-75% of the time when I am doing focused practice. I would buy another at the current high price.

I've been using metronomes since the early Seventies, and I've tried a lot of different kinds. The best solution I've found is to use a cell phone metronome app. I use the app in combination with a chorded or wireless, single, earbud connected to the phone. The app I use is called "Simple Metronome" and is available for free from the Play Store.

Using a single earbud, I hear the metronome in one ear and the banjo in the other. The app allows you to control the volume of the metronome click so that it's not drowned out by the sound of the Banjo. If you don't like the sound of a click, the app offers a wide variety of other sounds.

Wittner Taktell mini. Available on Amazon

I like one called Metronome Beats by stonekick for my Android phone. In particular you can set up different drum patterns. I like it - a simple thump on a kick drum on the downbeat and a snare drum on the offbeat.

I also like to run it at Double speed. In other words, if I'm playing 90 beats per minute, the metronome is set to 180. That has really helped me get my notes spacing evened out.

I tend to learn songs at 50 to 70 BPM (that's a good speed to make up breaks too). Then repetition at 80-90. Then, gently upward (Although I am not a speedster).

swing-arc.netlify.app/