As a general rule of thumb, a 5 year old RV will be worth about half of the original selling price. Example: if a new RV is sticker priced at $100,000 and sells for $80,000, then at the 5 year mark, it should be worth about $40,000 on the average market. That means the person that owned it for the first 5 years has lost $40,000 in depreciation, or $8,000 a year. Those are real dollars, which many owners don't like to even think about, as you can tell from some of the posts. The depreciation slows down considerably after about 5 years, give or take.
Fun can be very expensive, not just with RVing. We all tend to have some limits to our disposable incomes, which varies from person to person. Most of us involved in RVing, accept the costs involved. For rough operating costs, I tend to think in terms of about $1 a mile, not counting depreciation or loss of investment income, on that money. This would be using the RV for 10,000 to 15,000 miles a year and spending a month or two sleeping in it. Less or more of either will make the costs vary.
So many variations in costs, as mentioned above. Miles per year, maintenance costs, self done or shop done work, camping costs, insurance, depreciation, storage, and other items such as lawn chairs, grills, etc.