This summer, my trailer was towed empty for almost 500 miles, and then subsequently I loaded my boat on it and drove it another 200 miles or so to get my boat home. During the latter trip, I noticed that the tandem axles were uneven, and the two tires on the rear axle were really low - in fact I thought at first they were going flat. I stopped and tried to put air in them, and realized they were full and started worrying - I had to get the boat home, so I took it real slow and watched out my mirrors constantly.
I made it, and dropped the boat in the water and when I inspected the trailer, it seems one of the spring-holders attached to the equalizer had somehow become inverted during the trip when the trailer was empty (must have bounced over something...?). I jacked it up, got a long crowbar and made what I thought was the correct adjustment. Turns out, I stupidly flipped the side that was in the right position to match the one in the wrong position!! Here's what I did:

I ended up take it to a trailer repair place, and the boys flipped it back for me (for free...!). Here's how it looks now, both in the correct position:

Caught a break and learned an important lesson!