Say I don't ever click the "New Identity" button, but just have the regular browser bundle running for some days. I'm guessing my identity will change since nodes are not always up, but does Tor enforce creating new routes at some interval? (If so, how often?)
3 Answers
First of all, Tor builds new circuits regularly - that has been covered in For how long does a circuit stay alive?.
However, the New-Identity button in the Tor Browser Bundle does more than just rotate to a new, unused circuit. It also tries to clear cookies and maybe more in order to make your future requests unlinkable to your previous web visits.
That property you don't get at all just by waiting for some time.
Short answer: 10mins.
Long answer: I quote from Tor FAQ:
Tor will reuse the same circuit for new TCP streams for 10 minutes, as long as the circuit is working fine. (If the circuit fails, Tor will switch to a new circuit immediately.)
But note that a single TCP stream (e.g. a long IRC connection) will stay on the same circuit forever -- we don't rotate individual streams from one circuit to the next. Otherwise an adversary with a partial view of the network would be given many chances over time to link you to your destination, rather than just one chance.
Also please see "For how long does a circuit stay alive?".
Your identity will change every 10 minutes.
Tor will reuse the same circuit for new TCP streams for 10 minutes, as long as the circuit is working fine. (If the circuit fails, Tor will switch to a new circuit immediately.)But note that a single TCP stream (e.g. a long IRC connection) will stay on the same circuit forever -- we don't rotate individual streams from one circuit to the next. Otherwise an adversary with a partial view of the network would be given many chances over time to link you to your destination, rather than just one chance.
Text from Tor FAQ