You're not likely to burn the rubber off of them and as long as alignment is kept in good shape there should be no reason to change tires anywhere NEAR that often. Pretty much the same rules apply to RVs as any other vehicles. when tread wears down or they reach 5 or 6 years after the manufacture date.
2011 F-150 HD Ecoboost 3.5 V6. 2550 payload, 17,100 GCVWR -
2004 F-150 HD (Traded after 80,000 towing miles)
2007 Rockwood 8314SS 34' travel trailer
US Govt survey shows three out of four people make up 75% of the total population