Power down disk drive or not - when used two or three times per day

[Chris Green]

This isn't really a specifically Ubuntu question but I can't think of
anywhere better to ask it.  The backup system in question runs Ubuntu
though.

I have a 'remote' (in my garage, many metres from the house) backup
system.  It has an 8Tb external USB drive used for backups.  Systems
in our house use rsync to do backups to the backup system in the garage.

The backups run from /etc/cron.daily and I have adjusted things so
that they happen in the small hours of the morning around 2am or 3am.

There are two systems doing regular daily backups and one, which isn't
always turned on, that does occasional backups, maybe once a week.

The backup system boots and runs from an internal drive and so it only
accesses the external USB drive when doing backups.  The USB drive
spins down after some minutes of inactivity.

Is it *really* a good idea to spin down and up twice (or occasionally)
three times a day (plus of course any use I make of the backups) or
should I configure a 'keep alive' process that stops it spinning down?

Power consumption is trivial, so power saving isn't an issue, I'm
more concerned about longevity.  Is it going to wear out faster
spinning all the time or is it going to be better not spinning most of
the time but spinning up two or three times a day?

If it's of any relevance the USB drive is a WD Elements one.

(The question arises because I have just moved the backup system from
a Raspberry Pi to the Ubuntu one, the Raspberry Pi didn't always spin
up the USB successfully so I had a "keep it spinning' process there)

-- 
Chris Green