We are on the beach 3 to 4 Xs a week, unless they go in the water, most of the sand is off before they get home, Tiki is the swimmer, I towel him off briskly before loading him into the truck, very little sand. A dryer is my next investment, but the sand is not a big issue, & I have 3 dogs & live a block from the beach.
Mud is more a issue than sand, in my opinion.
Also depends on the consistancy of the sand, in OC, the sand was dirtier than the sand in NJ (between Point Pleasant & Lavallette, our range), some beaches are of a dirtier type sand, some are more hard pack.