I am not really sure how the mats develop, except that sometimes there is an undercoat that contributes...but it is my opinion that as the dog blows his puppy coat, if the coat is thick enough, the hair never falls out and gets all tangled up with the growing hair...that's "matting according to Jacque" :?
But I will say that when the matting is extreme (and it sneaks up on you...it's not anyone's fault, it just happens) then it is best to clip it off. You can do it yourself (I do ours very carefully, with sissors) or hire a groomer. If you are not inclined to be very patient, I'd say hire a groomer.
It takes FOREVER to get every mat out AND the worst part is that you can so easily nip the skin with sissors. You don't think you are getting close, but loose skin can pull up and you can cut it...so please be very careful.
Matting is very uncomfortable for the dog, sort of like when people are wearing tight braids (I know, you men out there have no idea what I mean) and it really pulls...and gets worse with water and time.
So, if you have mild matting or no matting, I'd suggest complete brushing every other day, or at least once a week. Use a dematting brush if you can find one. (Les Pooches, mat zapper, etc.)
But if your dog won't hold still for brushing near feet, ears, belly...it is so much easier to go to a groomer regularly.
I have to do my own grooming because I have too many dogs, but if I only had one...you bet it would be a groomer doing this!