re: Kubota wants you to replace the fuel line every 4 years regardless of condition. Why???
Probably cause they're 'Made in China' and Kubota has zero confidence that they'll last 8 years of 'normal' use ? I seriously doubt anyone does extensive actual 'Real World', proper testing of the hoses(combnations of heat,cold, fuel additives, vibration,variable pressures,etc.) .Yyeesh, it's 'just a hose' ,right ?? They just buy the cheapest they can( increases profit) and get the new owner to 'replace every 4 years', betting it'll last at least 5, just past the 'we told you so' time limit.
Now if you want 'lifetime' hoses, make them from steel tubing or use hydraulic hose. Yes, up front cost is higher BUT over say 40 years, you should have replaced the OEM one 10 times !