I do find it useful if the separation is made by project or by such a topic that cannot be found through search. A folder for each sender is redundant, you can

I do find it useful if the separation is made by project or by such a topic that cannot be found through search. A folder for each sender is redundant, you can filter your mail and get the same result. Best is if you can apply the GTD methodology and sort the incoming email in what needs immediate attention, what can wait a bit, etc... I use this with work emails. For my private emails I have a topic based tagging/folder technique.