Quote from: CoTi on November 03, 2014, 09:34:52 AM

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Quote from: patt0 on November 01, 2014, 08:56:08 AM

Quote from: CoTi on October 31, 2014, 05:54:53 AM

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Quote from: karthus on October 30, 2014, 04:32:33 AM

Understand basics like the following:

1. Learn to back up your wallet balance
2. Learn to save your private keys and do not share them
3. Learn bitcoin balance typo errors can be made eg: 0.1 when you meant 0.01
4. Learn bitcoin is a non reversible payment
5. Learn to use reputable escrow with +1 or higher
6. Know in the bitcoin world of business anything can be gone within in instant.

Is backing your btc wallet really necessary?

I suppose, it is unnecessary if I just buy/sell. is it right?

Yes if you want to keep your bitcoins online without having a wallet on your computer, but I don't know if that is very safe.
If the site goes down or is hacked, you could lose control of the bitcoins. : /

Online shared wallet are not 100% secure. The operator have full control of your Bitcoins, try using wallets like blockchain.info and enable 2FA. Since they do not have any control over your Bitcoins, you will not lose them if they get hacked or run away. It is pretty much secure from hacker too compared to normal desktop wallets as they need 2FA code to access your account.

so to protect my wallet well is the most important thing. Can I copy the wallet to another place then delete it after I update it?

You can but there is a risk. A hacker may seize the chance to get your wallet before you delete it if you do it offline, I suppose there is no problem.