Say you want a taller ceiling in your basement so its usable...

[Roger Simons]

There's going to be an awful lot of earth that needs to be moved out if you're digging down much.  I was thinking about this and how egress doors are usually preferred by tenants (as long as its not a very high crime area).  So I wondered why not dig in through the sides first so there are openings (say 2 to 4 for a medium sized house.  The more openings the easier it would be to get all that earth out.  Surely that's one of the main problems of doing this kind of extensive renovation.  Or is this usually the way its done lowering basement floors?  Or do they just use one then repair the wall later as it was?  I'm surprised at how egress entrances seem to be often ignored by house hackers.  People pay quite a bit more for a private entrance.  If that private entrance has a small kitchen they would then be completely self contained. 

Another issue of space management is deciding if one could do this without any hallways in the basement.  Every room would have its own private egress door instead.  You'd have to have a window as well for fire safety I think.  Hallways and the stairway down to the bottom floor waste a LOT of space in most houses that aren't huge.  I don't know if I've ever seen this done though.  Have any of you?  Another thing to consider is when you have a door that opens to that hallway, you can't have anything in front of that door.  That also wastes a lot of space.  Even if the door is sliding its a problem because you need to walk through so you can't use shelving there.  One option might be to build the shelving with a door like hinge so part of the shelving itself opens up to the hallway.  

Maximization of space:  We've been at this since the Stone Age.