How often or should you change out Tranny fluid

A friend of mine owns a transmission repair shop for the past 30 years. he told me that if the color of the fluid is the same, leave it alone. If it smells burnt it will also change color. I agree with

the poster who avoids Jiffy Lube. :( . We never flushed our trannies years ago, why now? Drop the fluid, new filter and go. Allison transmissions are bullet proof. Worked in trucking based

industry with 500 in our fleet, very little failures and very abused in their daily usage. Excellent product.