The 'just CLA it' advice for sluggish focus rings is wrong way more often than people admit
I've had four cameras cross my bench in the past month alone where the owner swore the focus ring felt gritty and they were about to soak the helicoid in lighter fluid. Three of those four had a bent filter ring putting pressure on the front group, and one had a slightly swollen rubber grip that was rubbing the barrel. Not a lubrication problem at all. I get why people jump to CLA, it's the catch-all fix and it feels productive, but pulling a lens apart when the real issue is a $12 filter ring or a grip that needs a hair dryer and some patience is how you turn a 20 minute job into a three hour one. I started keeping a cheap set of feeler gauges on the bench just to check for barrel contact before I even think about opening anything up. If you've been chasing a gritty focus ring and a CLA didn't fix it, what did it turn out to be?