This is the standard dogma of the Tor camp, however I fail to see it. If you keep the same set of entry guards for a year, only the entry guards, their ISP's and your ISP are capable of determining this. If your ISP, your entry guard, or your entry guard's ISP's are malicious, then you are at great risk of falling victim to a timing attack or a fingerprinting attack. It definitely makes you stick out (to your ISP, entry guards and entry guards ISP) if you use persistent entry guards, but I don't think it really reduces your anonymity in any appreciable way. The people who know that you are using those guard nodes already know who you are, and they already cannot tell where you are going unless they get you with a timing or a fingerprinting attack, and if they want to get you with a timing or a fingerprinting attack they are already capable of doing so. I have never gotten a satisfactory answer as to how exactly using persistent entry guards reduces your anonymity. That is the most acceptable answer I have ever heard regarding this subject. However, I would point out that if the attacker operates one of your entry guards they are able to attempt timing and fingerprinting attacks against you regardless of if you stick out or not. I can see a possibility that if you stick out by using the entry guard in a persistent way, that the attacker may decide to do non-traffic analysis based surveillance on you. That is the only way I can see using a persistent set of guards as possibly being detrimental. Although if everybody on SR starts using persistent entry guards, then using persistent entry guards will become a behavior associated with SR. But if only you use persistent entry guards, out of all of the people here, and you never tell anybody that you do, it seems like a bit of a stretch to me that this hurts anonymity (although this is what the Tor people claim, so I am not finding fault with your description at all). I would be absolutely furious to learn that a vendor looked up my address on Google Maps over Tor. I would also be furious to learn that a vendor looked up the tracking number on my package over Tor. Although it is probably common behavior, thankfully none of the vendors I work with would ever do such things though.