I think that checking ground connections at least once a year is just one of the joys of trailer ownership and part of routine maintenance. A good connection to bare metal using a star washer and a bit of dielectric grease is really the best you can do as far as the wiring itself is concerned.
However, many trailer light issues have nothing to do with the trailer light sockets or a ground connection on the trailer itself. Instead, the issue can be traced to a poor ground connection between tow rig and trailer. A pin on the tow rig socket and a pin on the trailer plug are dedicated for this ground connection, so test that connection FIRST when troubleshooting a problem. Then check the ground between your 4-pin/7-pin socket to the frame of your tow rig. Finally, test the grounds in your trailer wiring.
I carry a piece of 8 gauge wire with heavy duty clips on each end for the express purpose of ensuring a proper ground between tow rig and trailer if/when trailer lights fail mid-trip (usually in the middle of the night in bad weather or if I am in a hurry to get someplace). It has resolved 90% of my trailer light issues and allowed me to get to my destination where the issue could be resolved permanently in greater comfort.