Something to consider. Are you going to very clearly tell the surfers, in a way they can absolutely
not miss before they sign up for a membership, that there are daily download limits? (Does that even sound like a good reason to join a site to you?)
I'm not sure why you're interested in doing this, but there may be a better way to achieve the result you really want, unless of course what you really want is just to limit your members enjoyment of your content in whatever way they choose.
Are you having a big problem now with too many members logging in and downloading the whole members area? Is that, or something like that, what's driving your interest in limiting how much your paid members can download each day?
Remember that not everyone uses a member area the same way. Some will login every day to enjoy content online (and those members want to see new things added regularly or they'll cancel). Others will login every so often and download a bunch of content to enjoy offline. And yes, some will try to download everything they can soon after they join. But unless you clearly state how paid members are and are not allowed to access the content, those members would be well within their rights to believe they can do whatever they want for the next month once they've paid their money.
Done wrong, your plans can cost you more in lost members than any perceived 'loss' you might incur from members downloading content they believe they have a right to download.
Just my opinion here of course.
