My Technitop was on for a few years. Then the cover formed a leak, water entered the folded tent. A strange white fuz grew on all of the fabric, the mattress became moldy, the zippers all oxidized and are stuck, the steel frame rusted, the ladder rusted, the rest of the metal has oxidation on it.... I don't live near the ocean, so salt is not a problem.
I cleaned the fuz off with bleach water, the zippers are still stuck/broken, the mattress cover was saved to template a new cover, the foam was trashed, the frame and ladder can be cleaned and painted (yes, the galvanized ladder needs paint now). So, with some effort and someone to repair (probably replace) the zippers, I might have it useable again. I am now deciding on whether I want to sell it as-is or fix it. I am also looking at getting a new tent.
The moral of the story. If you can take it off, I would. I would also inspect the cover regularly. It really sucks having such a big investment fall apart due to a small leak.