Do I need an external surge protector? Other essentials?

Been RVing since 1971. We're on our 7th RV and never have needed a Surge suppress. and never damaged anything. We do Test pole polarity with the cheap 3 light tester and the pole voltage under load with our $25 Kill-o-Watt meter. The most important thing is never run the Air conditioner Compressor if the line voltage is under 107 VAC. The lower the voltage the more current the compressor uses and it gets hot and fails over time.