You don't want a wheel falling off your trailer. That could be one very bad day. Besides a wheel bearing failure you could easily have the lug nuts loosen. The next thing you know the trailer wheel passes you as you go down the road.
The torque setting for your trailers wheels is generally greater than it is for your car or truck. Plus the trailer nuts loosen easily. On your car or truck the wheels actually turn as you go around a corner. OK - at least the front ones turn. Your trailer wheels are fixed in place. This means that when you go around a corner the wheels actually flex. This loosens the lug nuts, for bolts.
You can't just tighten the lug nuts with a bigger wrench because you might break the wheel stud. That's an even bigger problem. The solution is to tighten them correctly and do it several times.
People say you should do it until the nuts actually stabilize. I'm suggesting that you do it after 50, 150 and again at 300 miles. You should be fine then until the next time you remove a wheel. Then you get to do it all over again.
If you're taking a decent size trip with your trailer it's not a bad idea to go around the trailer and check all the lug nuts on the trailer before you leave on any trip.
Torque Specifications: Wheels Bolts
M10 - 40 lb. ft. / 54Nm
M12 - 65 lb. ft./ 88 Nm
M14 - 108 lb ft. / 164 Nm
Torque Specifications: Wheel Nuts
3/8" UNF - 42 lb. ft. / 57 Nm
7/16" UNF - 50 lb. ft. / 67 Nm
1/2" UNF - 56 lb. ft. / 76 Nm
5/8" UNF - 85 lb.ft. / 115 Nm
Keep in mind that the measurement is the diameter of the bolt, not the size of the wrench you use to tighten them with.