JBC CD-1D w/T245 owner here and hate it. Tips are quickly oxidizing garbage, just a few sec and it is dark and solder wire rolls back on itself and not sticking to the tip.
My tips have corroded too.
I believe mine might have as well, however... I've had my iron set at 325 C with a setback temp of 150 C. The usual solder I use is Kester 63/37 Eutectic rosin core solder over a variety of tips for both of my irons. I use minimal dwell time and when I'm ready to replace the iron, I apply solder, remove by a gentle and quick wipe over the corner of the shock sponge, reapply more solder, then place in the holder. I only use the heavy wool if serious contamination is present and that's not been often. I turn the unit completely off unless I think I'm going to use the iron again within a minute or two.
With that mentioned, I performed maintenance and repair on a variety of items (most consumer repairs) at least 3 to 4 times a week for the past year and still perform quite well and wet very easily. I've only used tip tinner twice in the beginning, which I almost thought my tips were ruined, but were easily wetted with minimum controlled solder after some rewetting with the usual solder I use.
These are just my results so far, however... I believe once I need to use a harsh lead-free solder with an acidic flux, any tips used are going to be very short lived. I'll report back when the situation arises.
In regards to my Pace MBT-250 w/SX-100 desoldering iron, I've set the iron to roughly 335 to 350 C. I've abused the tips by doing lots of the things that shorten tip life, including desoldering lots of SAC305 and other lead-free alloys with extended dwell times. After each extended period, I've followed the Pace recommended barrel clearing procedure before replacing. I remove the tip and turn the iron off if I'm not using it more than a few minutes. Each tip lasted about a year or more. This is not realistically convenient, nor cost effective for most practical uses, however these are the results I've experienced with this procedure.
Again, I'm speaking only from my experience on my own rework equipment.
EDIT: I forgot to mention that occasionally I use an old Pace ST400 IR preheater on any board I think would need it.