My go to Metcal tip for general purpose use is a STTC-144 Conical 30deg sharp bent 0.5mm
I also have a couple of Conical 0.4mm tips as well, however for really small components, however all of these tips are too large for the pads being soldered, so I'm looking for a smaller tip for occasional use.
It seems that as tip size decreases, the tip becomes more fragile and likely to oxidize.
Metcal/Thermaltronics offer tips as small as 0.1mm, 0.2mm, 0.23mm and 0.25mm.
These will typically be used for rework of a lead free board, where I use leaded solder after the rework.
I would really like to hear from anyone that has used these smaller tips, regarding longevity and if one you had to chose one particular tip in this size range, what would it be?