On just about every camper we have had it was plugged in to 30amp power 24/7. The last 2 were motorhomes and always plugged in except when we were traveling or were going to be out of town for a while (non-camping).
That said I am not sure that keeping it plugged in is a real good idea. Why you might ask? On the Monaco Dynasty we had, the refrigerator caught fire while plugged in under the shed at the house. After the fire department responded and the inspector gave his opinion, he said it was electrical failure. Totaled the motorhome. I feel (felt) it safe to keep it plugged in all the time but if we replace the Monaco with something else, I don't think I will keep it on power all the time. Guess I am skittish at this point.
If you do keep it plugged in then keep a close eye on everything!!! Be careful out there.