USB sticks are more vunerable to memory loss than a standard Hard Drive. In older or less expensive sticks the solid state memory can degrade over time, newer technology used in SSD "hard drives" is better. The same was true at one time for CD ROMs but this has gotten significantly better over time as well. The rule at one time for CD-ROM was "use write once CDs for backup and multi R/W disks for everything else." This has probably changed!