Cool tool kit , One of my favorite things I've purchased was a Zepp Spray bottle from Home Depot and filled it up with IPA . I can make a bottle of alcohol last for months now on my farm and using Microfibers towels to clean the bed instead of rolls of paper towels.
The pfte fittings that you have not had to replace are something I personally replace a lot and actually have chosen all my newer print heads to avoid entirely using direct drive. They do get loose and sloppy after a while and you can feel the bowden tube wiggling in and out. This makes blobby prints. When they fail entirely you'll get not just a print of spaghetti on the bed but the unprinted filament roll gets spurted out from extruder and you have spaghetti all over the printer. You can rewind it back on the roll in that case but overall I dislike those fittings and pick print heads that do not use them at all, such as BMG to v6 which allows zero use of any bowden tube.
The standard threaded M6-10 bowden fittings have made me rage on a number of occasions, because when I go to perform maintenance and try to remove the bowden tube it just won't let go, despite cranking down on the collar of the fitting and yanking on the tube to try to release it! I give up and have to unscrew the coupler just to be able to remove the bowden tube. When you tighten it down to avoid heat block leaks, I find that the teeth get more and more stubborn over time, and it basically becomes impossible to remove without unscrewing the coupler, which can be a pain in the ass depending on how accessible it is on the hotend mount that you've got. On the other hand, the inset collets that come with BMG extruders and V6-style groove mounts have been excellent, and I've never had a problem with them actually letting go of the PTFE tube.
