Many folks sell their house. They invest the money for the future. Everyone is different. Many retirees don't want the big house and yard to take care for in later years and still many don't want to live in a harsh climate. Keeping a house is added expense and worry if you leave it vacant or if you have renters. Putting your furniture in storage is a big expense. Later on if you buy in a retiree community you can find many homes or Park Model trailers for sale that come completely furnished. If you've thought out your plans and you're both onboard for full-timing then go for it. It's a big weight off your shoulder taking off free with no baggage behind.
We had never heard of full-timing until our first winter travels. We talked to so many that were extremely happy. That spring we retuned to our 2500 sq ft lake house with a big yard and sold it and everything in it over the summer and never looked back.
Only those who have done it can tell it like it is. :)