To folder or not to folder ... that is the question

As Susan says, not either/or. Rather a both/and. Some tips

• Attend one of Susan's sessions! She speaks regularly at Microsoft conferences, SPTechCon, SharePoint Saturdays. Better yet - engage her firm's services. Susan's is a leading practice in this space. (Ok Susan - you owe me a drink ;-) )
• Harness end user instinstics by automatically assigning metadata values using Column Default Value Settings. Defaults can be set on folder-by-folder, column-by-column bases. Values are inherited from parent folders. Touchless for end users - as long as governance well established and users put files where they belong
• Layer lightly. I generally keep it to 3 levels max
• Metadata - even 'metadata light' - is the gift that keeps on giving:
  • Can help bubble up the most relevant content when searching
  • Easy to implement at chosen scopes when using content types and term sets: farm, site collection, subsites, x-site collections
  • Combine closed taxonomies with open folksonomies (great way to get user feedback on the fly. Move the most commonly used tags (enterprise keywords) over to your defined vocabularies (term sets) from time to time
  • Content types with defined metadata columns make user adoption easy - esp with default column values
  • and so much more ...
• Save end users from endless drilling up and down to find their files by creating folderless views
• Last - far from least and most exciting - click that funnel icon in a modern library. You'll find pre-populated filters based on modified dates, modified by, folders ... and automagically ... by metadata and other signals identified by mining the Office Graph and other deep machine learning going on behind the scenes. Very very powerful. Becoming moreso. End users will start seeing immediate benefit to sacrifices made to metadata alters