....during summer, I park the truck camper (Outfitter Caribou 8) rig partially under a tree canopy (hardwood maple and white ash and beach, giving shade to the softwalls but for only ~2.5 hours a day; so, I have very little sun hitting the softwalls during summer at our camper parking area) with the roof up all the time (and if expecting rain, I lower it down). So, from end of April till about 2 days ago (it went into heated storage for winter), or nearly 6 months, the roof was in the up position (except when raining).
Over winter in the heated storage facility, I did, one year, store the camper with the roof up the entire 6 month-ish winter. I stopped storing over winter with roof up because cleaning the Weblon softwalls the following spring was getting very old-- and this was the one and only time (it was filthy!).
Some pop-up truck camper manufacturers suggest keeping the roof up when not in use for extended periods....this may be because the softwall pleats endure a lot of stress when folded (I know the pleats on our Weblon softwall appear to have more wear than the unpleated softwall, for sure). I have to add, that our Weblon softwall is very, very, VERY stiff, and does not move but for a fraction of an inch, even under gale-force winds.
What you do would be based on your camper manufacturer's recommendations, and the outdoor environmental conditions.
