Securely Empty Trash

If you've been doing this on an SSD, you're wasting your time, and only increasing the number of writes. This only serves to reduce the lifespan of an SSD.

There's no such thing as a secure erase on an SSD. That's why it's not in the OS menus anymore.

What state secrets are you trying to prevent anyone from accessing? Only data that valuable is of any interest to criminals who would try that hard to recover it.

What you can do is use FileVault to encrypt the drive with a strong password (if you aren't already). Anyone else would have to be able to supply the password in order to get at the data. Either at startup, or coming back from the screen saver.

If at any point you want to replace the drive, then it's easy. You simply boot to Recovery Mode and erase the drive. That wipes out the key and no will ever be able to access the encrypted data. Install a copy of the OS to the drive while you're in Recovery Mode to ensure the file table is overwritten with new data on top of having been erased.

You're welcome. 🙂