On Thu, 17 May 2018 07:49:55 +1000, Peter Jason wrote:

I have many USB2 & USB3 going back 10+ years, and
now some are "socket specific" on my 10 YO
computer motherboard (some USB3s will work on some
sockets; even USB2 sockets) and not others.

Do these thumb drives last forever, or should
their contents be transferred to the latest USB
drives?

The number of write cycles determines the life. Many manufacturers
specify 10,000. If that's true, the life expectancy is not likely to
be exceeded in normal use, like storing files or using it to transfer
files from one device to another.

That said, the use to which flash memory is put can also determine
it's life expectancy. If, for instance, it is used in a data-logger,
back-ups, or recording system where the data is re-written or
written-over in the course of normal usage.