Things you should know about sd:
* Be careful where you buy from. There are a lot of 'fake' cards out there, small cards hacked to report a higher capacity than they have to the phone and then sold as big cards. The phone thinks the card has more space than it really has and so doesn't realise that the card is full and it is overwriting the data that are already on there.
So don't buy from anywhere where you can't reliably take it back, and under no circumstances buy SD cards from eBay or some Chinese online market. If a deal seems too good to be true it is 100% because it's a scam. And remember that 1TB microsd cards do not exist in reality (so anyone selling those is also a scammer).
* Android intends SD to be used for media storage. Don't bother moving apps there, it's really not worth it on a Note (or anything that isn't desperately short of space), just use it for media.
* Do not assume that data are safe because they are on SD. Sure, if the phone breaks you can take the card out, but if the phone is lost or the card fails (it does happen) you lose the data. So if it's important, make sure you have a backup that isn't on the phone.