First, establish what you want to protect your car from. Here is an overview of the possible risks, in which storage locations they may occur, and the features that a cover should have to protect your car from them.

RISK

- where may it occur?

required feature

DUST

 - anywhere

dust tight

SCRATCHES

 - anywhere

soft

sturdy

non-scratchy

inner lining

soft on paint

to protect from scratches by sharp edges on zippers, garden tools, bikes etc.

If a car cover does not fullfil all of the above requirements, there is no point in using it.

But, depending on the storage conditions there may be additional risks,requiring extra features from the car cover:

RISK

- where may it occur?

required feature

UV-RAYS

- outdoors

- carport

- indoors when parked near

  window or under glass roof

UV - resistant

CONDENSATION

- outdoors

- carport

- indoors in

  unheated space

breathable

to allow moist to escape when it evaporates

RAIN

BIRD/TREEDROPPINGS

- outdoors

- carport

water tight