user13327: After reading this question I watched the keypoololdest. 

It was 1392447127 (Sat, 15 Feb 2014 06:52:07 GMT)
I created a new address.
Then, it was 1392449568 (Sat, 15 Feb 2014 07:32:48 GMT)

Should the time change to be today at the moment of change? It is too old (like one year ago) . If I took a backup now is it sufficient until the "keypoololdest" changes to be more recent than the date of the backup?

user9382: The keypool, as the name suggests, is a pool of keys stored in your wallet.dat file for various functions including:

change addresses
new addresses

By default you'll have 100 keys. Each time you use a key for change or receiving, there'll be one less key in the pool. A new key is added to replenish the used key.
The oldest key (from February 2014) represents the age of the oldest key. In other words, you're storing BTC at an address that was created in February 2014. Replenishing the keypool doesn't update the date because that would mean the private key for the oldest (and still useful!) key has been cleared. 
There's no inherent issue, per se, with old keys, if they're secured. 
(Although encrypting your wallet will replenish all keys since a compromised wallet would reveal a sizeable portion if the now encrypted keypool) 

user30396: The value 1392447127 is exactly Sat, 15 Feb 2014 06:52:07 GMT in  Unix timestamp 
check it here : http://www.onlineconversion.com/unix_time.htm
keypoololdest gives the unix timestamp of the oldest key in the key pool (which stores unused keys). This timestamp can be used to check if a wallet backup still covers all your used keys or a new one needs to be created.
At the latest, if the timestamp retrieved with keypoololdest gives a date younger than your youngest backup, you should create a new backup.

13327: <p>After reading this <a href="https://bitcoin.stackexchange.com/questions/35572/how-many-addresses-does-my-wallet-dat-contain-do-i-need-to-make-a-new-backup-ev">question</a> I watched the <code>keypoololdest</code>. </p>

<ul>
<li>It was 1392447127 (Sat, 15 Feb 2014 06:52:07 GMT)</li>
<li>I created a new address.</li>
<li>Then, it was 1392449568 (Sat, 15 Feb 2014 07:32:48 GMT)</li>
</ul>

<p>Should the time change to be today at the moment of change? It is too old (like one year ago) . If I took a backup now is it sufficient until the "keypoololdest" changes to be more recent than the date of the backup?</p>
 9382: <p>The keypool, as the name suggests, is a pool of keys stored in your wallet.dat file for various functions including:</p>

<ul>
<li>change addresses</li>
<li>new addresses</li>
</ul>

<p>By default you'll have 100 keys. Each time you use a key for change or receiving, there'll be one less key in the pool. A new key is added to replenish the used key.</p>

<p>The oldest key (from February 2014) represents the age of the oldest key. In other words, you're storing BTC at an address that was created in February 2014. Replenishing the keypool doesn't update the date because that would mean the private key for the oldest (and still useful!) key has been cleared. </p>

<p>There's no inherent issue, per se, with old keys, if they're secured. </p>

<p>(Although encrypting your wallet will replenish all keys since a compromised wallet would reveal a sizeable portion if the now encrypted keypool) </p>
 30396: <p>The value <code>1392447127 is exactly Sat, 15 Feb 2014 06:52:07 GMT</code> in  Unix timestamp 
check it here : <a href="http://www.onlineconversion.com/unix_time.htm" rel="nofollow">http://www.onlineconversion.com/unix_time.htm</a></p>

<p><code>keypoololdest</code> gives the unix timestamp of the oldest key in the key pool (which stores unused keys). This timestamp can be used to check if a wallet backup still covers all your used keys or a new one needs to be created.</p>

<p>At the latest, if the timestamp retrieved with <code>keypoololdest</code> gives a date younger than your youngest backup, you should create a new backup.</p>
