When purchasing a HDD these days, you might want to pay attention to what recording technology it is using. In the past, pretty much all drives used Conventional Magnetic Recording (CMR) where tracks are written side-by-side and do not overlap.

Beginning a year or so ago, all of the major HDD manufacturers began slipping Shingled Magnetic Recording (SMR) drives into their product lines --- WITHOUT telling anyone. With SRM, the tracks overlap much like shingles on a roof. The upside of this is greater track density which leads to using fewer platters and heads than CRM drives and then, ultimately, to high-capacity drives that cost less a lot less to manufacture. The downside is that SMR handles using/releasing free space in a complicated/inefficient way and in some applications that activity can create serious problems. If, for example, you are filling a backup drive by creating large backup images, deleting an old image and immediately writing a new large backup file, or if you are using a RAID array you'd be well advised to ensure any new drive you purchase is a CMR drive.

SMR does result in lower performance, but it enables cost savings that are attractive to some users, and if used in the correct types of workloads, those savings are worth the exchange of gaining access to deeper capacity. However, using SMR tech for desktop and laptop boot drives will likely remain a topic open for debate, as their underwhelming performance in sustained random write workloads could hamper performance in standard operating systems.

Considerable information, analysis, and discussions about this are easily discoverable with Google.