We have always covered our vans, for at least the last 20 years.
Our last wwb was immaculate when we sold it.
We live opposite a wood so they will go green quickly.
But covers also keep the sun/UV off the van.

I popped into the storage unit the other day to make sure my Triton was Ok. It was sat there very happily in its secondhand Kampa cover (ex eribaMotters) and has needed no extra straps or attention. I even manage to put it on and off on my own! That's two years it has done now and still looks like new. We've had some strong winds recently, but all OK so far - unlike the caravan next door to ours...!

I'm trying to add some photos, but the uploader keeps crashing...

Aha! Working again this morning.