I saw it again today on my way into work, a boat trailer on the side of the road with a blown bearing and tire completely shredded. I am no expert and if you have any doubts always get the proper advice from a professional but there are some simply things you can do to make sure you are not the one stuck on the side of the road with a broken trailer on your way to your favorite fishing spot.
1) Check the tire pressure on both your trailer and tow vehicle. Make sure they are properly filled and do not exceed the limit stamped on the side of the tire.
2) Grab a tire wrench and check the torque on those trailer tire lug nuts. If you want to be precise grab a torque wrench but really all you need to do is try and give them a spin to the right (righty tighty lefty loosy) with the trailer on the ground.
3) If you have bearing buddies installed on your trailer, make sure you add some fresh grease to keep them cool.
4) If you have a floor jack at home, jack up the trailer and check for play on each tire. Simply put your hands at 12 o'clock and 6 o'clock position, pulling and pushing each hand. If you feel the tire moving you have play in the hub and this is one of the first signs of a problem. Repeat this putting you hands at the 3 o'clock and 9 o'clock position.
5) If you trailer is equipped with brakes make sure to have a look at those. With the trailer jacked up spin the trailers and make sure the pads/shoes are not dragging.
6) Before driving off, do a check of you brake and signal lights. With these properly working, you won't have to worry too much about the guy driving behind you and taking out your prop.
7) Once at the ramp, don't put the boat in right away. Ensure you check for heat at the rims and hubs on the trailer. If they feel just a bit warm that is ok, let them cool for a minute or so and then launch your boat. If they feel hot, you are on the verge of a problem. Try and book a time into your local shop or your own garage and get those bearing re-packed.
As always, for the first outing of the year, make sure you top of the fuel tank in the boat with fresh gas, top up the oil reservoir if you have a 2-stroke and charge all those batteries (not just the trolling motor battery). The last thing you need when you finally get on the water is having problems in this area.
Lastly, do not forget to unhook those straps and put the drain plug in before getting the boat wet

A little preparation can go a long way to a enjoyable fishing trip and this won't cost you a cent, just a bit of your time.
Good luck fishing on the long weekend.
Mike