I work at a lube shop and recommend among other things transmission fluid flushes/changes at manufacturer intervals. Customers have two ideas on atf. 1.If it still looks good, why should I change it? 2.If it looks bad, I was told by (brother, boyfriend) to never change it again. So if customers generally subscribe to these beliefs, when will the fluid ever be changed? Usually when the transmission starts slipping. they come in for one last try to fix it with a flush and bottle of Lucas. At which point it helps for a week and then goes bad again. They fix the tranny finally, maybe $1500. Next time the service interval comes around for the new transmission. They will still deny service, claiming last time they changed the fluid the tranny failed soon after. See we Quick Lube techs dont have it easy.