I have just finished reading the posting on arma's blog about entry guards and I'm trying to reconcile what I have read there with what I (think) I understand from other postings about Tor.
First, I assume (please tell me if I correct or not) that a new set of guards is selected each time a user initiates a Tor session, so the remarks about retaining guards for periods of 6 to 12 months would suggest that some Tor sessions are of extremely long duration. Is that correct, and are there any statistics about the distribution of duration of Tor sessions?
Second, there are several warnings, in other Tor guides, not to mix different identities in the same Tor session. I understand that to mean that, if I use a pseudonymous identity of Frank in one session and access websites that recognize me as Frank, then I should not also use the pseudonymous identity of George (to access the same or different websites) in the same session. Again, is that correct?
Third, how does one reconcile the apparent desirability of maintaining guards (and, therefore, presumably a session) with the "don't mix identities" warnings.
I would very much appreciate some clarification both of whether my understanding is correct and of the apparently competing risks/benefits. Alternatively, if there are particular documents that I should read to clarify a misunderstanding or to answer my own question, then I would appreciate a pointer to those docs.