Only takes one time. I plugged into a shore station (MINE installed by an electrician) and it was wired wrong, cost me around $3,000 to replace all that it fried.
I was coming home from a very very long drive and arrived late at night dead tired. I pulled in excited to be able to hook up right in my own yard in her new RV garage I had built while I was gone. Surge protector was in the bay and I just pulled out the cord without it and plugged in. :(