1. Check the air pressure in your tires and don't forget the spare
2. Inspect your trailer tire's treads and sidewalls, looking for cracks or lack or tread and replace as necessary
3. Bearing should be inspected and repacked if necessary
4. Test your tail lights, brake lights, turn indicators and back-up lights
5. Test your trailer's winch to make sure it's working properly and inspect the cable or strap for excessive wear
6. Inspect your trailer frame for rust and sand/paint to prevent further
7. Repair or replace damaged rollers and bunks to prevent damage to your hull when launching
Remember...flares and fire extinguishers should be inspected for expiration dates before boating season begins.
Replace any expired units. Think safety first!