Bob is correct, that the size of the yurt could be a determining factor in whether you choose to dismantle the yurt or leave it up. Smaller yurts are quicker and easier to assemble and dismantle, so it wouldn't be a too much of a burden to do this occasionally. Larger yurts are often left assembled for longer periods of time due to the time and energy typically spent assembling and dismantling the yurt.
If you choose to leave the yurt in place year round be sure it has the appropriate features for the site/climate. Also be sure to heat the yurt and vent excess
(by opening the dome) before closing it up for long periods of time (if using a modern yurt).