HEATER HOSE 1/2" BORE PER METRE

Original mini half inch bore heater hose cut to metre lengths as required. The MK1/2 had one hose 35" and one at 16" long, MK3 had one 35" and one at 29".(These are all maximum lengths). Please note MK4 1976 on some had 42" heater to bottom hose. Why not upgrade to the more expensive but stronger kevlar hose to save failures(GRH1006KEVLAR)or the special silicon hoses C-GRH1006 & C-GRH1007?