Just wondering what would be the amount of memory that should be free on Curve 8310,i'm currently running the following:

OS 4.5.0.42

Applications:

BB Maps
Doc togo
Google Maps
Jive Talk
Opera Mini
Viigo
Vringo Facebook
Iberry Theme
Precision Theme

I've done the optimization as per JC sticky, my free memory is currently: 13,647,716 Bytes, is this right?

I would personally be concerned with only 13mb free. I like to have it around 20mb; I don't have any third party themes...

Sounds so. Check out blackberryfaq.com on ways to regain. I personally turn off logging (hold ALT+LGLG an dturn logging off), I remove unused modules, remove autotext and anything else unnecessary and gain back a lot of space. Granted I only have two or three apps installed. Hope this helps. Also see link below...

How to Increase BlackBerry's File free memory - BlackBerry Forums at CrackBerry.com

There's not really a "should". It all depends on what you have loaded in device memory and that consists of preloaded apps & content, apps that you have loaded, your data (PIM & email) and any media that you have loaded in device memory which should really be on the media card.

I've run for months with far less memory available (currently at 9MB but I've been at 8 or less). You just need to keep an eye on it.