To answer the OP's question...we had a 2008 Bighorn. Back then they were NOT warranted for fulltiming in writing as they are now. We had some major issues in the warranty period...Heartland was WELL aware that we were fulltiming in the unit as we brought it back to the factory several times. NOT once was it ever questioned and they covered our rig from top to bottom, both during and after the warranty period.
Their unflinching customer service to their owner's, fulltiming or not, is why we stayed with them and now own a 2013 Landmark!!
P.S....In addition, they have the ONLY customer service department that I've seen with and RV manufacturer where they answer the phone!! No machine, no recordings...they answer and send you directly to a CS Rep in your area. If you are handy, they will also send you parts so you can avoid the dealer and make simple repairs yourself. Case in point, the little motor that makes the "flames" in our fireplace went out. Contacted the fireplace manufacturer...what a run-a-round, AND they wanted $95 for a $3 motor that was just over 1 year old!! Finally called Heartland...they are obtaining motor from fireplace manufacturer and sending it to us directly...free of charge!!