I modeled my living room after following the tutorial. I had a bit of trouble understanding when to parent objects together and when to join them. Also I tried a bit of texturing for the first time but nothing much just the floor and the chair. Overall I had fun modeling my stuff ! :)
This is much better than mine was. Great job.
Nice work!
Parenting objects would be used in animation, for example if all the objects on the table were parented to the desk, and the desk was moved everything on the desk would move with it, whilst still being separate objects that can be moved independently, the lamp can be rotated toward the keyboard, the mouse can move over the mouse pad etc.
The desk is the parent, the mouse, lamp, computer etc., are all children of the desk.
Remember: 'The child always goes where the parent takes them, but the child can also wander away from the parent'.
Joining objects with CTRL+J will consolidate two or more objects into one object. For example, with the sofa you may model the frame, the seat and back cushions and the smaller side cushions as separate objects. Then join the frame, seat and back cushions into one object, to move them separately you would have to enter edit mode and select the verts you want to move, whilst keeping the small cushions as separate objects which could be parented, as with the desk example, and moved easily to a different position on the sofa.