Accord2005NJ

Hi,

I have 2005 Accord 4cyl Auto (if it is relevant). My question is general in nature;

If you drain tranny fluid every 10-15,000 miles, do you ever need to replace 100% of tranny fluid. It is my understanding that draining replaces only 1/3 of tranny fluid so is there a point (i.e. at 100,000 miles) at which (instead of doing a drain) one needs to (and how?) replace 100% of the liquid?

Also, is there anything "bad" about draining the fluid every 10k miles?

Thanks.