A Thunderbolt dock is like a deluxe USB hub. It will let you connect not just USB drivers and peripherals, but also connect to monitors, Ethernet, audio devices, and more. I’ve been using a CalDigit TS3+ Thunderbolt dock with a Mac mini for the past few weeks, and it’s pretty good.
The CalDigit TS3+
At $250, the CalDigit TS3+ is one of the most recommended docks around. It’s Wirecutter’s top pick, and reading around the web, there’s almost nobody saying anything bad about it. After using one for a while, I have to agree. It gets hot, and it has an annoying blue LED in the front, but it has been completely reliable for me. But first, what does it do? The TS3+ comes with a (large) power adapter and a Thunderbolt cable. The latter is important, because a decent Thunderbolt cable can cost around $30 on its own. You plug in the power, then connect it to your Mac (or PC). With this single cable, your little MacBook Air now has:
5 USB A ports2 USB-C portsDisplayPortEthernetSD Card readerAudio in/out jacksDigital optical S/PDIF audio connectorAnother Thunderbolt port
The dock also powers and charges the MacBook via the same cable. At first, the layout seems a bit weird, split between the front and the back, but in practice it makes sense. The more permanent connections are on the back, whereas less-used ports—SD card, headphones—are on the front. Also worth noting is not all those USB ports are equal. Only one of the USB-C ports is USB-C 3.1 gen 2, for example. The other is the slower USB-C 3.1 gen 1, matching the USB A ports. For our purposes, you just have to know that the gen 2 USB port is twice as fast (10GB/second) as all the others (5GB/s), so that’s where you should plug in a fast, external SSD. Connected to the dock, I have an old USB 3.0 hard drive for backups, a Dell monitor (via DisplayPort), and a fast USB-C SSD, where I keep my photos and other large files. That’s it.
Displays
My monitor can also connect via USB-C, but if I do that, then the Mac mini won’t connect to it on boot. I contacted Apple support, and they said they’re working on a fix, but until then, DisplayPort looks just as good. It does mean that you need to run a second USB cable to the monitor if you want to use the monitor’s own USB ports, but between the dock and the Mac mini, there are plenty to spare. If you’re using an Intel MacBook, then you can connect two monitors to the dock and use both simultaneously—one via DisplayPort, and one via the spare Thunderbolt port (which is also compatible with USB-C monitors). With an M1 MacBook, you can only use one monitor without hacks. The M1 Mac mini can power two displays at once, although one should be connected to the mini’s own HDMI port.
In Use
I have very few complaints about the CalDigit TS3+. One is that it runs hot, but that’s apparently a Thunderbolt thing. Still, it’s ironic that the dock is always way hotter than the computer. Apple’s M1 Macs never get hot. The other “problem” is caused by the Mac itself. Because M1 Macs never really sleep (they’re more like iPhones than PCs and older Macs), they often connect to the dock, even while the Mac itself doesn’t properly wake. This trick is sometimes called “dark wake,” and it means the dock’s blue LED lights up whenever this happens. This may not bother you. If it does, you can tape over the LED. In conclusion, the CalDigit TS3+ is a competent and reliable accessory. You’re probably going to need some kind of port expansion on your M1 Mac, because they have so few ports of their own. If you’re willing to spend the money, then Thunderbolt is a great choice, because it does everything over a single cable, including power. And this particular dock, in my experience, does the job just fine.