My 3DS needs replacing, need some info on data that will carry over

[Captain Goomba]

My 3DS is almost 10 years old (Year of Luigi, came with M&LDT!) and it's starting to fade. If I bought a new one, what would and wouldn't transfer over if I signed in with the same account? (I know physical games are written to the card, but what about stuff like digital games and the Badge Arcade badges? I have over 1000 of those puppies and don't want to lose them.)

 

[Ray Trace]

If you have game cartridges, saves are stored in them. If you digitally downloaded them, they should be downloaded to your SD card (in fact, most of your apps are downloaded to your SD card). Your SD card also stores update and patch data, as well as photos and music and badge data. Really, I think you're save upgrading to a new one if you feel your old one isn't much service anymore. Not sure where Miis are stored in. I think the only thing that won't be transferred over is play time and play data.

 

[Captain Goomba]

OK, cool! Thanks, good to know.

 

[Revin]

If the original system still works and you do the proper system transfer (which is the only way to transfer accounts anyway), basically everything will be transferred over exactly as it was: games, friend code, miis, play time records, all of it. Software wise, it'll be like you never "changed" it
Source: i did this a few years ago (nintendo support probably has a page with official information about it as well if you can be bothered looking it up)

 

[Captain Goomba]

What if I attempt to transfer to a 3DS that already has an account on it? My brother said he'd sell me his and the ones online apparently sell for crazy prices.

There's also another... not really an issue, just something I'd like changed. My 3DS account is actually linked to my dad's Nintendo account. I'm assuming you can't, but would it be possible to transfer the data to my account or no?