You can't convince me that keeping the fluid in there (with the typical non-bypass, coarse media ATF filter) has merit. Each shift event puts wear material, i.e. "swarf" into the ATF - and said swarf is an abrasive for the spools / pistons / seals inside of the aluminum valve body, serving to wear it out sooner as a result. Further, the anti-friction (i.e. rolling element) bearings, are running then in their races... with part-ways abrasive fluid as a lubricant, again serving to wear them out sooner.
I do not hold this out to fact, to be absolute... but even if I am partially-right, the cost of dropping the fluid (or dropping the fluid 2x in succession) every 30,000 miles or 40,000 doesn't even register on the radar, by way of cost, compared to losing and A/T - and the car then being written off due to the high A/T repair cost. Some of the Japanese 6 or 8 speed A/T's are prohibitively expensive to rebuild (if you can find someone to actually rebuild them).
For me, tight-media bypass filtration, 30, or 40 thousand mile changeout intervals (2 drops in succession), an auxiliary ATF cooler (downstream of the rad-tank cooler) - plumbed/valved so i) ATF can be shunted around it in, nominally, wintertime; and ii) rigged so that a pan-mounted bung / temperature switch controlling the rad fans can be used. For me, that's the ultimate setup.