Surge Guards, to buy or not to buy

I first bought mine 7 years ago. I was camped at an RV park in Nogales, AZ waiting to cross into Mexico the next day (It was the Bates motel of RV parks, BTW). A guy in a class A pulled in and I asked him if he was headed into Mexico. No, he told me, he was on his way home after 1 week. his fridge board was blown due to bad power. Next morning i doubled back to Tucson and got a surge guard. 7 years of RVing in Mexico later, the thing shuts down often 3 or 4 times a day due to low or high voltage. All my electronics re still intact.