SSDReporter Free

SSDReporter Free is a macOS app for checking the health of internal solid-state drives (SSDs) and flash storage. It reads drive health information from compatible disks and can notify you when the reported health decreases or falls below warning or error thresholds.

• Shows drive health with a status icon that changes from green to yellow at the warning threshold and red at the error threshold; the icon can optionally appear in the menu bar.
• Can send alerts by email or on screen when drive health declines or crosses a threshold.
• Supports internal SSDs that provide online S.M.A.R.T. data and useful health or lifetime attributes.

Install with brew install --cask ssdreporter-free. The app is free of charge and is supported by promotion of the developer’s other apps.

Only internal SSDs are supported; drives connected by USB or FireWire do not work. eSATA- or Thunderbolt-connected SSDs may work if their enclosure supports S.M.A.R.T. Compatibility depends on the drive providing the required health data. The developer lists macOS 10.14 Mojave or later as a requirement and states that technical support is no longer available.

Sources: SSDReporter · Homebrew cask