Spiderline and Fireline have virtually no "memory" as you word it - although modern lines have nearly no memory at all. Changing lines every six months is just fine.

There is not "no memory" line, there is low memory line from several manufacturers. Don't let the line sit on the real out in the sun for long periods of time and the same for cold temperatures. Finally change your line about every six months or sooner if you need to. You can look at the line and tell when it needs changing.

Fireline is suppose to have little memory. Good luck finding line with no memory, I am not sure if they even make it. Would be a great invention though...

Try braided line. It has different quirks than mono but well worth it. I have been using 15# test on a Diawa Advantage 2500 for one year straight and have not had one incident of any coiling or memory. 15# braid = 6# mono diameter. Extremely limp.NO MEMORY!! Florida fishing 24/7

DON'T HAVE A GOOD ANSWER,BUT DO I EVER UNDERSTAND THE QUESTION.
I USE SONIC 20# BRAID ZND SO FAR IT IS THE LIMPEST I HAVE FOUND.
I SUSPECT IF THERE IS A no MEMORY LINE IT MAY BE COST PROHIBITIVE ?

I AM SO FED UP WITH MONO I SWEAR I WILL NEVER USE IT AGAIN, BUT A LOT OF MY FISHING BUDDIES USE NOTHING BUT MONO IF YOU MUST FISH WITH MONO THE BEST I HAVE FOUND IS SOME VERY INEXPENSIVE LINE CAlLED "WORLD WIDE SPORTSMAN CAMOUFLAGED PREMIUM LINE IN ONE POUND SPOOLS".

I THREW THIS BALL IN BASS PRO SHOPS COURT AND THEY DRIBBLED. I RECENTLY BOUGHT MY FIRST BAITCASTER COMBO AND WANTED TO RIG IT WITH A LONG CASTING, NO MEMORY LINE OF ANY PRICE. THEIR ANSWER WAS "IT DEPENDS ON WHO YOU ASK" WHICH OF COURSE DOES NOT ANSWER MY QUESTION.

I SUPPOSE ALL OF THIS AND YOUR GREAT QUESTION DOES SUPPORT THE "ART" OF ANGLING. WILL IT EVER BE A SCIENCE? I AM READY FOR A BIT OF OBJECTIVE SCIENCE.

I WISH I COULD ANSWER YOUR QUESTION

SINCERELY

old timer