I did lots and I mien lots of reading on this after towing an enclosed trailer for years with zero issues. I never even bothered taking a spare tire. I may have gotten sloppy as I know I didn't check tire pressure as often as I should have. I parked the trailer at my parents house for years on a concrete pad and in the shade and it offered lots of protection that it doesn't get at home. Quality as we knew it also changed during this time. Over the years I also added more weight to my trailer in the form of a bigger quad, more tools, more supplies. The big thing the full time RV'ers said to do is as I said above. Add more pressure, 8-10 pounds more. Craigslist home improvement guys are always looking for used tires for their smaller, lighter trailer so I know I will be changing mine out more often. I also carry a spare now and I bought one of the drive-on tire lifts and it works great.
http://www.summitracing.com/parts/eqt-01/overview/