With the exploding popularity of ransomware, it's a good idea to have backups of at least your data on external drives that are not normally connected to anything, but safe on a shelf or in a drawer -- if you can see the files while using your PC/laptop, so can ransomware. Worse, they're starting to include worm-type capabilities in ransomware, so if anything on your network can see the files, they're not safe either.
There are 2 common ways for external drives to connect to a PC/laptop -- eSATA & USB. eSATA is better, but since USB 3.0 is both fast & easier to use, eSATA has become much less common. eSATA is basically the same SATA that drives use to connect internally in your PC/laptop, but tweaked to manage longer cables. Ideally a PC's motherboard will have an eSATA port or 2, which is extended to a port on the front &/or rear of the case if/as needed. Using a regular SATA port on the motherboard can work, but mileage will vary considerably, in part depending on the eSATA cable, it's length, & how it's routed to the drive -- seriously, you might have to move the drive all over the place, changing the cable's positions to get it to work. There are add-on cards available, but the bandwidth [how fast it will transfer data] will most likely be limited. And depending on the motherboard, you may have to connect a eSATA drive before you boot the device in order for the drive to be seen. Like I said, USB is easier to use. ;)
USB is not entirely a bed of roses either... The USB chipset in your PC/laptop, &/or the one connected to the drive may have compatibility issues, & the one connected to the drive may be unreliable for sustained data transfer. You can *usually* go by reviews regarding the reliability of external hardware, if there are enough of them, but when it comes to compatibility between external hardware & your PC/laptop, often you're on your own, having to just try it, so make sure that you can return anything you buy. And when you do try it, don't just stick to a copy of Windows -- as possible try to see if it works as a bootable drive, if it works before Windows starts, if it works on every OS you've got installed. I've experienced problems with all of the above, & while it's manageable when you have one or a few PCs/laptops, more than that can become a Big hassle, so you'll often see pro's recommend staying away from USB drives entirely for businesses with more than a few PCs.
It's not always easy to find, but there are temperature requirements for hard drives -- exceed that & drives can fail to work properly. Hard drives designed for different purposes can have different tolerances, e.g. you often have more airflow in a PC case compared to a laptop, & laptops by their nature are intended to be used in a wider variety of environments, so you may find some laptop drives hold up better if run hotter. SSDs don't have the same temperature restrictions as mechanical drives, but besides being more expensive, if the data being stored is critical, you might want to look at the reliability data for a drive before you use it -- you have a certain amount of failures writing & reading data to SSDs, so they have models designed for more critical applications rather than just speed.
Personally I tend to use cheap &/or old drives that I've pulled from daily use because they've gotten old -- BUT, I use more than one, so the odds are if one fails [& even new drives fail] I'm OK, & they're not doing daily, constant duty, which might help when it comes to longevity. Ransomware doesn't do it's nasty biz immediately, & once it starts encrypting files, that takes time too, so there's a period of time between becoming infected & realizing you're infected. If one of my external drives was connected during that time, it could be rendered useless as a backup, so having that data on more than one drive is another safeguard. So rather than having one expensive drive, I prefer much cheaper drives, but more of them.
Now to me there's no perfect hardware for external hard drives. You can buy external housings that have a built in fan or fans for cooling, & they can work very well, but it can also be a bit more hassle storing & hooking up & disconnecting multiple external drives, each in their own housing or case. I've got an external drive housing without a fan that I bought simply because it was so cheap, & it's smaller so easier to store, but the drive heats up too much for constant use, e.g. sustained data transfer of 30+ GB. I bought a drive dock, & being able to swap drives without connecting & disconnecting a USB cable & wall wart each time is nice, but the hassle there is the extra desk space needed because I have to use a 6" desk fan to keep the drive cool. Ultimately I bought another dock with a built in fan, but that was a DIY project rather than something that worked out of the box.
Made by Sabrent, the fan grills were extremely restrictive -- I pulled both, & glued a simple finger guard on the bottom. At the same time I glued the fan wires in place -- a manufacturing design fault, those wires when lose get pinched by the case during assembly, & I was surprised in fact that as badly pinched as they were, the fan still worked. This dock also sits too close to the desk for airflow, so I added taller rubber feet when I reassembled it after pulling the grills. And there's little way for the airflow hitting the bottom of the drive to go anywhere, so I added a couple of self adhesive Velcro strips [the softer half] to the rear of the drive tray to raise the drive slightly. Too much work maybe, but I was unable to find a better alternative.
amazon[.]com/Sabrent-External-Lay-Flat-Docking-EC-DFFN/dp/B013WODZH0/191-6106098-1197903?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00
