Hard drives (including external HDs and flash sticks) shouldn't be counted on too long...
Friendly reminder after I had one go bad on me. Everything I've read says 3-5 yrs is the norm, so I can't complain with 7 yrs, but I "leapfrog" my HDs with two separate backups, so after that HD fried I got another. Very inexpensive to do now and much of what I'd lose is irreplaceable.