Requires crimped fittings so hose P/N or spec needs to be exact when ordering especially with 2 angle fittings. Bend radius limitations vs rubber hoses is some cases. As mentioned additional cost. It's a bit of overkill on non-turbo recips but have seen them used on TC and E/AB aircraft. The advantage to teflon is there is technically no life limit vs rubber hose.
From my experience, yes. Have seen some go more than 20 years in certain installations. Most teflon hoses are usually changed due to condition issues: chafing, kinked, corroded fittings if applicable, etc. The main failure cause of teflon hoses in my experience is improper installation.
The practical in-service limit is "on condition" for teflon. All hose usually has storage life limits which should not be applied to "in-service" life limits. There are also some ADs/ALSs that assign teflon hose life limits but mostly due from mechanical issues vs teflon issues. The go to reference in most cases is the hose mfgr. specifications like the one below.
Hi Dave... as you know I have no turbo, however the idea of a fuel leak in the engine compartment is a source of nagging worry. For less than $700 I can replace every fuel line firewall forward with the Teflon hoses. I just finished the annual on 14V only to find fuel leaking from the fuel control valve. So off to Great Planes for a rebuild. Replacing hoses at 15 years seems like cheap preventive maintenance... and like you say new hoses, new parts just look great and that gives me a good feeling!
