Should i cover my caravan?

Recently bought my first caravan, an immaculate 18 year old Eldiss with no trace of damp, mould and no smells. The previous owners never covered it over winter, they used a few of those damp absorber thingys.

A friend of mine who has an 15 year old caravan says if he'd had his time again he would have covered itover winter because its a bit mouldy.

I intend to use my van occasionally over the winter, he doesn't.

Any views?