helps but not a cure-all
I bought 3 of these to use on my pooches in the horse fields, which get extremely muddy in winter. They were all were a bit small for my dogs, so be generous when you measure up. you will need extra for movement.
of course dogs come in all shapes and sizes so the leg or body length may be too short for one and too long for another, but i have found it to be fine for my collie.
I am generally happy with the one i am able to use (remainder given to friends) although it is surprising how the mud can work the way up the legs and underneath. but like i say i am using these in extremely muddy conditions so may fair better in more average conditions.