One of the most convenient ways to back up your MacBook is to subscribe to iCloud. After all, whenever you're connected to Wi-Fi and your computer is plugged in, it automatically starts syncing everything. However, this also means you need to rely on a subscription for as long as you want your data backed up. On the other hand, another solution is to rely on local backups so that you not only own your data but also won't have to rely on subscriptions, cloud servers, and more. If you don't connect your SSD to your MacBook and something happens, your latest backup could be a few days, weeks, or even months out of sync.