Like others said 5 - 6 years for all RVs is wise. Most often when a tire blows the tread comes off and flings around often doing thousands of dollars of damage. Tires have a date when made. You can search and find lots of info. Some times you may buy new tires that are years old. So need to watch what they sell you. Cost of new tires on most RVs is not near as much as fixing the rig after a failed tire tears it up. Our C got all new tires last year and cost about $1200 dollars. Friend just fixed his trailer where a 8 year old tire came apart and took out the heater, fridge and stove. Cost was $12,000 and off the road for 3 months. New tires would have saved him time and money.