Expected life of Hot end PTFE i.e. ID stays  

Expected life of Hot end PTFE i.e. ID stays

Hi - what sort of life ITO of meters of filament or colour changes can one expect from the PTFE in the hotend i.e.  ID will stay close to the 1.85mm or less than 1.95mm (orange tube from MMU to hotend)?  When I assembled the hotend with the 2.5 +MMU2 -> MMU2S +2.5S I used one of the PTFE tubes provided. The ID was definitely less than 2mm after a couple of months or so the tip sizes were getting to 2.2mm, I was unable to complete any multi colour prints. I disassembled the hotend and the ID was 2mm+. I replaced the hotend  PTFE again to the 2nd one provided (I confirmed that the ID was less than 2mm).  I had to replace the rambo board at the same time 24 June.  Since then I have been working with support to get my MMU2 working as I was getting MMU fails and MMU power issues.  After 464m of filament and 2xColor Benchy + 2x Friendly Dragon + one roll of wood fill + some single PTFE prints - by no means extreme usage. Today I had to strip the hotend as I had a blockage and I checked the hotend PTFE and it the ID was already 2mm or greater - is this normal for the hotend PTFE to expand in such a short period of time? I can only determine that the ID is 2mm as i use the shank of a 2mm drill bit to check.