[spuggy]

Sold-state (flash) drive long-term reliability is a factor of build/part quality, software quality (of the wear-levelling algorithm used) and the total # of writes (typically 10,000 per individual sector).

Important for an SSD disk you're using for a main system drive (where speedup can be tremendous).

For an impromptu backup drive you use once a week? Sure, go for it with any old $10 USB stick. Also take a backup to DVD now and again and stick the files in the cloud if you have no privacy concerns (or encrypt them if you do).

Certain popular OS's may eat your data at any time; for example, after a power fail you might find yourself stuck with dozens of "recovered" (but unusable/unidentified directories) containing 100's or "recovered" (but corrupted and useless) files.

Backups just aren't optional if you care about the files.