Me, too, and your reminder about line flexibility is worth filing away in the memory bank (as long as I can remember where it's filed)

I use a "Tygon" from McMaster Carr that seems to remain flexible, and has "TYGON" plus the spec # printed on it.... seems to have held up properly so far, not getting inflexible.

Do you have a "preferred" source of good Tygon and Neoprene that is 'real' stuff?