I still have two or three long term customers that I do this for...at no charge. They're close by and elderly, so it's not a big deal. And we're just talking a few plants.
I lost about 10 blankets when I left them with a customer one year. The next year he claimed he didn't have them. Hopefully he found them, because he has to do it on his own now. I now retrieve and store all my covers.