For several years, we did not use a surge protector. We did check the post with one of those lighted power testers before we plugged and we never had a problem. Then one day, we were late getting set up, we couldn't find the tester (because it did not get put back in its proper place) so we just plugged in. Never had a problem before so didn't figure we'd have one this time. Wrong. The 30 amp outlet was incorrectly wired as a 220. Well we kissed the converter, microwave, refrigerator control board, 2 TV's, satellite receiver and a fan goodbye from that little omission. Insurance, minus the deductible, covered the converter, microwave and refrigerator control board because they were "attached" to the RV. The rest of the stuff was on us. Expensive lession. We got the Progressive Industries EMS for that RV. When we traded RV's the first thing we did was install a hardwired PI EMS. Yes it was over $300 but it was still a lot cheaper than replacing all the other electronics. Do what you want, but we will never be without one.