Is it nessacery to switch sd card when you switch towns?

[Ably.Saucey]

Hi there, I'm not sure were to put this topic so I'm putting it here and if it goes somewhere else, I'm very sorry.

I play two towns, and I find very conflicting answers on whether you have to switch sds along with the cartridges.
Some say you have to use two sds or your town data will corrupt, some say you don't have to, just turn off the street pass for one of the towns and the rest say it you can just switch games like any other game cartridge.

Any Insight would be helpful

p.s, I've been switching sds just to be safe
Thanks

 

[Aubrey895]

I never switched sd cards. I had five towns

 

[BrinaLouWho]

I've also never switched!

 

[Ably.Saucey]

That's great! Thanks guys! This is going to some me quit a bit of time when cycling! Thank you again!