Just curious about staining around the mouth

[Gumbo and Ashley]

So, as I'm looking thru hundreds of photos here on DK, I noticed that the lighter and white colored doodles will often have brown staining around their mouth. Some pics I wasn't sure if it just looked darker because their mouth was wet from drinking?  I was looking at one particular dog's pics and in some his face didn't have the staining and then in others it was quite noticeable. My question is, is this a permanent thing that all light colored dogs get?  Is it avoidable? Does it go away and then return? Does it just happen from them always playing outside and in the dirt?  Some dogs get it so bad it looks like they've been eating dirt and poo. My Gumbo is going to be light colored, so I was just curious as to how to avoid this from happening or is it unavoidable?

[Jen, Buddy, & Kevin]

The picture of his stains is right below this post. Not sure why it didn't attach with the birthday picture?

I agree, Kevin knew it was his day and he was having a blast! Just by chance, we ended taking a vacation with the boys the week of Kevin's birthday. So, he had been hanging out in Mendocino and the giant redwoods up in humboldt county that week.

[Jen, Buddy, & Kevin]

Oops, stains didn't upload. Hope this works.

[Wendy and Myla]

I don't know about the staining but he has the bestest blackest nose ever!  Love it!  :)

[Jen, Buddy, & Kevin]

Awwww, thanks! :-)

[Gumbo and Ashley]

He totally does!! I agree 100%. So dang cute!

[Gumbo and Ashley]

Ok now I see....hmm....I think it actually looks cool on Kevin. LOL... It almost looks like hair dye. I think what I'm confusing is just a dirty wet mouth and the actual staining. Even tho Kevin, has staining, he still looks very clean and groomed. I think I've just been over loading my brain with too many pics of doodles with dirty mouths. If this is what I clean "staining" looks like, then I'm not gonna be too concerned if Gumbo gets it. LOL. 

[Sue, Murphy and Bella ()*o*()]

This made me have to stop and go look at my dogs faces. They both have some staining, one is apricot and one white-white, but I have gotten so used to it that I couldn't really remember it without looking. Bella is white and has some staining that is brownish along her lip line and lower beard, but it seems to wash off somewhat and she never has any smell to it. Her face will never be all white, no matter how short I cut it, as it's just saliva staining and you can't prevent it.
Murphy has some darker hair around his mouth, but with him too, I just don't notice it all that much. It's just part of their look I guess.

[Breanna]

Crush's is barely noticeable because her ears are darker and her back is dark. It looks like the same color. When she was spayed, the hair around the incision grew back dark. I thought that the surgery changed the coloration but the vet said it was from her licking it (ew). People have remarked how gross it is that the hair is dark around her potty area too...Not that her privates are any of their business.