-- Last Updated: Dec-26-12 8:52 PM EST --
1. Keep the bearings greased; make it easy by having grease fittings (Bearing Buddies) on them, and you can grease both wheels in a few moments. And make sure you use WHEEL BEARING grease intended for high-temp applications (small wheels rotate faster for a given mph than big wheels do).
2. Keep the tires up to pressure. This means not airing them down too much, as so many advise. With such a light load as kayaks, you don't need to put the maximum pressure in them, which might be 65 to 80 psi for some tires. But you also should not let them go down to ridiculously soft pressures, because that causes overheating of the tires and uneven wear. On the Trailex SUT-350-M2 that I tow, the tires are the little ones with maximum pressures in the 60+plus psi range. Yet the trailer maker's decal says to use only 20 psi. I never go that high OR low and have had no trouble with hauling glass kayaks. I've put anywhere from 35 to 50 psi in them and settled on 38 psi. Tires are wearing normally and the ride is soft enough because of the soft leaf springs on that kayak-specific trailer.
Those are the two things to pay special attention to. But really, watching tire pressure is something you should do with your car anyway, so there's only one extra thing to watch for: adequate grease in the trailer's wheel bearings. And that is incredibly easy to do.
Now, for the bugaboo that you cannot control: In Colorado, tolls for trailers are extremely high. It wasn't always this way; things changed a couple of years ago and C470 Authority began gouging trailer users. It's based on number of axles, not actual weight or length. So my combined truck and trailer and payloads add up to less weight than a full-sized SUV with 1 driver and no passengers or loads at all. Go figure! But I sure wouldn't let extra toll or parking charges deter me from buying a trailer if it was better in other ways. (And C470 Authority and their incompetent recordkeeping can go stick themselves where the sun don't shine! Good riddance.)