Your wallet has a "pool" of addresses (100 by default) so you don't need to back it up after each transaction but regular backups would be advisable (also note that your wallet keeps the "labels" you might assign to addresses so these could be lost if not backed up).
There is no simple way to see all your addresses in the current version of bitcoin-qt (you can play around with the console if you are really keen) but if the new "coin control" implementation gets merged then there will be an "expert" mode that would allow you to.
All payments are made from what are known as UTXOs (unspent transaction outputs) which put simply are the "coins" that have been sent to you (including any "coins" that you might have mined).
Each UTXO needs to be completely spent when used to create a transaction - so if you have 1 UTXO of 1 BTC and you want to send someone 0.25 BTC then the *only* way this can be done is to create a tx with 2 outputs - one of 0.25 and the other of 0.75 (with the latter being a "change" address).
Also note that "fees" are simply the difference between the total of the UTXOs and the transaction outputs (so if you had nominated to pay a 0.0005 fee then the 0.75 amount would become 0.7495).
There is no simple way to see all your addresses in the current version of bitcoin-qt (you can play around with the console if you are really keen) but if the new "coin control" implementation gets merged then there will be an "expert" mode that would allow you to.
All payments are made from what are known as UTXOs (unspent transaction outputs) which put simply are the "coins" that have been sent to you (including any "coins" that you might have mined).
Each UTXO needs to be completely spent when used to create a transaction - so if you have 1 UTXO of 1 BTC and you want to send someone 0.25 BTC then the *only* way this can be done is to create a tx with 2 outputs - one of 0.25 and the other of 0.75 (with the latter being a "change" address).
Also note that "fees" are simply the difference between the total of the UTXOs and the transaction outputs (so if you had nominated to pay a 0.0005 fee then the 0.75 amount would become 0.7495).
Thanks, I get it now. I forgot the blockchain doesn't store amounts for addresses but only the transactions.
