wallet back up advice

[BitCoinNutJob]

Sup 

1.) should you back up your wallet after every transaction? - are there any cases of non recent wallet back ups not working?

2.) if you do back wallet up after each transaction does that mean after at least 1 confirmation on the most recent transaction?

ty

[vm1990]

you only need 1 backup copy of your wallet (most people do 2 not the entire wallet just use the file and backup wallet)
it can be a back up from your very first transaction. all transactions are stored on the blockchain which is backed up on every computer and server using bitcoin-qt the back up just tells you wallet what address is yours and the wallet searches the blockchain for all translations to and from that address

[Barek]

Bitcoin-Qt with default parameters at least every 100 transactions.

Other clients with deterministic wallet (Armory/Electrum), you only need to back up once.

[michagogo]

NO. What vm1990 said is wrong and could lead to loss of your bitcoins. With some wallets, such as Electrum or Armory, you do only need one backup of the wallet seed, from which addresses are generated. However, with other clients such as Multibit and Bitcoin-Qt address generation is random, and when you generate new addresses you need to back them up. I don't know how Multibit works, but here's a quick summary of how Bitcoin-Qt handles things. Bitcoin-Qt generates and maintains a keypool, 100 (by default) key pairs (and thus addresses) that are kept in reserve. When a new address is needed, either when you ask for one or when you make a transaction and a new address is used for the change, the oldest address from the keypool is used, and a new one is generated. The size of the keypool is configurable. When you make a backup, that backup is usable and complete as long as the last keypool address in the backup hasn't yet been used. This means that you'll need to make new backups of your wallet, at some point within 100 address generations (either for change from transactions or when you request a new address).

[vm1990]

NO. What vm1990 said is wrong and could lead to loss of your bitcoins. With some wallets, such as Electrum or Armory, you do only need one backup of the wallet seed, from which addresses are generated. However, with other clients such as Multibit and Bitcoin-Qt address generation is random, and when you generate new addresses you need to back them up. I don't know how Multibit works, but here's a quick summary of how Bitcoin-Qt handles things. Bitcoin-Qt generates and maintains a keypool, 100 (by default) key pairs (and thus addresses) that are kept in reserve. When a new address is needed, either when you ask for one or when you make a transaction and a new address is used for the change, the oldest address from the keypool is used, and a new one is generated. The size of the keypool is configurable. When you make a backup, that backup is usable and complete as long as the last keypool address in the backup hasn't yet been used. This means that you'll need to make new backups of your wallet, at some point within 100 address generations (either for change from transactions or when you request a new address).

you sir are either stupid or retarded....
a transaction is NOT the same as an ADDRESS. a transaction is either sending or receiving coins to or from the wallet. an ADDRESS is a newly generated address which is not done for transactions unless you have asked the wallet for a new address. in which case i would create a new backup after each address

a transaction is stored on the block chain so its downloaded from other people should you need to restore it
next time do research before accusing a sr.member or being wrong

the OP asked about backing up after a transaction which is pointless. aslong as you have a backup with the addresses you use then your coverd,
now if you create a new address (which for some completly random reason were now covering) you should create a back up after generating each new address as a safety messures

[BookLover]

In bitcoin-qt when you send a transaction the "change" is sent to an address in the keypool, so michagogo is correct in that you would need to backup your wallet after 100 (sent) transactions.  For proof look here: https://en.bitcoin.it/wiki/Securing_your_wallet.  It's under "Securing the Bitcoin-QT or bitcoind wallet", paragraph four, sentence three.

[michagogo]

a transaction is NOT the same as an ADDRESS. a transaction is either sending or receiving coins to or from the wallet. an ADDRESS is a newly generated address which is not done for transactions unless you have asked the wallet for a new address.

...Are you not familiar with the concept of change? Any time you send bitcoins from Bitcoin-Qt, unless you happen to be sending an amount that exactly matches a combination of inputs from your wallet, Bitcoin-Qt will automatically, silently, generate a new address in the background and send the change to that address.

in which case i would create a new backup after each address

No need. Thanks to the keypool, you only need to make a backup at least once every <keypool> addresses.

a transaction is stored on the block chain so its downloaded from other people should you need to restore it

The wallet doesn't store transactions. (well, it does, but that's not its main purpose, nor is it critical.) It stores keys for addresses. Yes, the transactions are in the blockchain, but this doesn't help you if you don't have the private key for an address.

next time do research before accusing a sr.member or being wrong

That is meaningless. All it means is that you've made a certain number of posts on the forum.

the OP asked about backing up after a transaction which is pointless. aslong as you have a backup with the addresses you use then your coverd,
now if you create a new address (which for some completly random reason were now covering) you should create a back up after generating each new address as a safety messures

As mentioned earlier, in the vast majority of transactions that you send, you will generate a new address for change. This is the same reason that you can't safely import a paper wallet into Bitcoin-Qt, spend from it, and then delete wallet.dat expecting the balance to remain on the paper wallet. And again, unless you set your keypool size to 1, there's no need to back your wallet up after every single new address you generate. It certainly can't *hurt*, but it's also not necessary.

[Luke-Jr]

Theoretically, an address and a transaction are just different ways to refer to the same thing.
An address is an identifier for a transaction that may not have been created/signed yet.

[michagogo]

Theoretically, an address and a transaction are just different ways to refer to the same thing.
An address is an identifier for a transaction that may not have been created/signed yet.

Note that this is referring to the ideal best practice of never reusing addresses.

[BitCoinNutJob]

thx for the input fellas just reading through, dont wanna start an argument here : ) appreciate the help

[Abdussamad]

thx for the input fellas just reading through, dont wanna start an argument here : ) appreciate the help

There is no argument. What michagogo said is correct. What you are seeing is the community correcting itself which is one of the beautiful things about open source.

[vm1990]

i stand partly corrected on things. still i have backed up a wallet done way over 500 transact and added the wallet on a 2nd pc and still had the correct amount in the wallet. maybe im magic i dont know but iv done it a few times and never lost any coins.

also on of the best ways i like to do backup is find a peice of software like ftp software that has the ability to sync files. i use it due the mass amounts of wallets i now use. much easier to sync it across an encrypted network to 2 secure pcs