Pfsense w/o hdd

[anothereric]

From reading around I've gathered that pfsense can be run without the
use of a hard drive, using only the live cd and, say, a usb stick to hold
my configs/rules.  Is this correct?

But if I want to use any of the optional packages, then I do need have a
hdd in my system, is this right?

Is there any other reason why a hdd would be necessary other than for
the optional packages?

Is there any reason why a hdd would be desirable?

TIA,
eric

[GruensFroeschli]

The additional packages usually access the harddisk a lot.
IE: squid uses to hdd to cache.

Standard flash drives have a limited number of write cycles. (10k, better ones 100k, industrial grade usually 1M+)
You dont have to use a hdd per se, but just a storage device which doesn't die after 100k write access cycles.