Every business eventually replaces its equipment - a laptop is upgraded, a phone is traded in, an old external drive is cleared out - and the natural thing is to sell, donate or discard the old one. What is easy to forget in that moment is how much of the business went through that device over its life: files and documents, emails, saved passwords and logins, browsing history, and quite possibly customer or financial records. A device at the end of its working life is not just old hardware; it is a container of everything it was ever used for, and it is about to be handed to someone else or left where anyone might pick it up.
The trap is assuming that deleting the files, emptying the recycle bin, or doing a basic reset has removed the data. Often it has not, in any reliable sense - deleted files can frequently be recovered with freely available tools, because "deleting" typically just marks the space as reusable rather than actually erasing what was there. People have bought second-hand computers and phones and found the previous owner's personal and business information still recoverable on them. For a business, that could mean customer details, financial records or saved access to accounts walking out the door inside a device you thought you had cleared, and possibly straight into the hands of someone who goes looking.
Doing it properly is not complicated, and the method depends on the device. For a computer, the reliable approach is to use a proper "securely erase" or full-wipe function - modern operating systems include a reset option that erases and, on current encrypted drives, effectively renders the old data unrecoverable - rather than just dragging files to the bin. For a phone or tablet, performing a full factory reset (ideally after confirming the device was encrypted, which recent phones are by default) and removing any SIM and memory cards does the job. For an old drive that is being discarded rather than reused, and for anything that will not wipe, physical destruction is the sure answer. If a device held especially sensitive data and you are unsure, a specialist data-destruction service exists for exactly this.
The habit worth building is simply to make "wipe it" a required step before any device leaves the business, the same way you would shred a sensitive paper document rather than putting it in the bin intact. It costs a few minutes per device and removes an entire category of quiet risk - the risk that your data has a second life on hardware you no longer own and can no longer protect. A device you are finished with is one of the few times your business's information physically leaves your control; making sure it leaves empty is a small discipline that closes the door behind it.