Glad you have not had any issues to date. Yes, the tires may go a while yet, if no cracks, bulges, curb damage, or overload. I would take a close look at bearings, give them a repack, with quality grease. In my experience buying new trailers of any type, the factory is very skimpy on the grease. If you have not adjusted the brakes since new, you will be surprised how much better they work after adjustment.
Some people are anal about maintenance. IMO, you should check things right away after purchase, even when you get a new trailer. After that, again IMO, bearings should go at least 3-4 years, depending on miles towed. Don't forget roof maintenance, and caulking around windows and seams.
Jerry