Quote from: btc123 on May 19, 2012, 01:32:16 AM

Good to know, thank you. Why is there a hard limit at 100 and what happens if I go over 100?
Several forums that I've read recommend that I use a new address for each transaction. That would add up real quick.

The client tries to keep 100 unused private keys available in a "key pool". So the first time an address from your wallet receives a payment the client then marks that address as being used which brings the number of addesses in the key pool below 100. The client then adds a new one automatically.

You can specify on startup a size of the keypool so that the client will keep a greater number or fewer number of unused keys.
- http://en.bitcoin.it/wiki/Key_pool