HPOP lines, when should they be replaced???

[STROKIN96]

...just wondering about the rubber hoses....I have never replaced them, there is no damage to them that I can see.( I'm the only one who has ever owed this truck..)... or should i wait till i get an Sd HPOP before I change the lines???? What about the "HX" mod....has anyone noticed a difference the way thier truck runs??

Thanks,
Carl