Warning: I swept for 6 years before I figured out my rods were the problem
Last Tuesday I was on a two story colonial in Cleveland and the brush kept binding up around the second flue bend, so I finally laid the rods out straight on the driveway and saw they had a slight bow I had been working around since I bought them in 2018. I swapped in a straight set and the same run that used to take me 40 minutes was done in 15, which means I was fighting my own gear on every job and blaming the flues instead. How do you check your rods for a bend without pulling them all off the truck?
Really, six years though? A slight bow in the rods is pretty normal and you can still get the job done. Sounds more like you just got lucky with a good run than anything.