have been read many times that addresse dont expire so you can send to old add even 6 years later.. is this correct?
but why does it have this "expires after" choice? what does it do?
I will like to add, just know that bitcoin addresses can not expire, so far you have your wallet active and you are able to access your wallet, you can use the address you have used 10 years ago. Even, if you lose your wallet, the address will not expire and you will be able to still use the address ones you can access it.
That aside, for privacy reasons, it is not good to reuse the same address for every transaction so your wallet balance can not be tracked or traced to a single address.
Also about this link
https://ibb.co/Jy9bHLQDo not get it wrong, it means you want to send bitcoin to another address, that the transaction should expire with the time you chose, there are some wallet that reverse back your bitcoin into your wallet if the transaction is never successful with the time taken.