On my last trip, I lost a good fish and when I reeled it, I found that the trace had snapped at the knot after the swivel. The lake I fished isn't easy and one chance in 24 hours is a result and then to lose it was a kick in the nuts. I tested all the rigs in my wallet and one failed quite easily but the others survived a good yanking with a couple of puller tools.
I have been using olivettes to pin down my main line but since buying the bait boat, it does cause the line to sink a bit too much. I went back to using a 30 foot fluoro leader on the mono so everything near the hook should be pinned down without the drama's of using fluoro all the way through. As fluoro can be a bit temperamental, I put the hook through the gridding on my barrow and gave the line a good pull to try to iron out the inherent coiling the flouro likes to do. On one rod, the line snapped without too much pressure. I was convinced it would be the back to back grinner but when I checked, it had gone a foot above on the mono. I must have nicked it putting it in the holdall and created the weakness.
I used to check every rod before casting it out but fell out of the habit. Today's thought is to check everything is sound before you lose that fish.