I don't know of anyone who has gone 100% digital. It takes time and effort to convert paper to digital format. The conversion has to add enough value to overcome the resistance to doing it. I can create a paper file in under one minute but I can't say the same about scanning and filing. It takes at least double that.
I have a processing station at the office and one at home. At the office I deal with very little paper input (though I do have a cubicle with a single filing cabinet drawer). I do not have a paper-based tickler file at work, but I do at home.