My 05 Accord just turned 30k miles. I think the transmission fluid needs to be changed. Just a little concerned as I've read some issues of transmission problems and failures.
Should I do this myself "DIY" or have the dealer do it so it will be documented for warranty purposes, and if there are any immediate problems related to the fluid change?

TIA

If you buy the fluid from the dealer (Honda ATF only) keep your recipt, and you'll be just fine.

I'd go ahead and log it in your maintenance section of the owners manual.