I have a relatively cheap 2 layer blue one, I don't use a white cover either since it became a real pain to continually put it on and take it off, so I only put that cover on over the winter. It's now lived 3 years and still going strong, so I assume the white cover really doesn't do THAT much for a longer cover life - I only expected 3 years out of this one, looks like I'll get 5-7.