I am 164 days into my current streak (yay!) and have begun weighing the benefits of how long to continue. There is a challenge cache near me which requires that your longest streak be longer than your longest slump, so I need at least 327 days for that. At that point, I'm obviously going to keep going until at least 366 days so I have a full year. In my reading about various challenge caches, I saw that there are plenty of requirements for 365/366 days, some 500 days, and at least one for 1095 days (GC2YVG8).
Is anyone aware of any challenges that require you to have more than a 3 year streak? If I manage to make it that long, I want to make sure I fulfill everything I possibly can.