As others have already said the 690 takes the knocks pretty good out of the box. Ive binned mine a few times and its come through pretty good with only scratching to plastics. Having said that I have it set up for adventure riding rather than hard out dirt stuff....not that it dosn't get that from time to time
If your riding on rocky tracks a better bash plate, a rear break disk guard and some bark busters would be a good idea. Too much stuff bolted on ya bike if you are doing tight trails can be a pain though and there is always the crash that no manner of protection will save you from.
The 690 is a big bike and can become a handful real quick in the dirt especially at speed...probably wouldn't be my choice for learning to ride dirt on but it is a very capable bike once you get used to its size. I'm sure you'll have a lot of fun on it!!