I don't put spaces in table names and field names, because those are used frequently in VBA and SQL: Me!Field1, Select Field1 From Table1, etc.  It's not like you can use aliases for them.  You have to reference their real names all the time.  So I agree with probably every database user on Earth that it's best to have a proper naming convention for tables and fields.

But I do use spaces in form names and query names.  In fact, I use free-form names for them: [My Collection Edit Form], [Query: Movie Titles by Country], etc.  And that's because I rarely reference them in code and SQL -- because I often don't have to.  I can avoid referencing a form by name by using objects like Me and Parent.  When I close a form, I use DoCmd.Close acForm, Me.Name.  When I reference a subform, I only reference the subform control's name, not the actual name of the subform.  And if I rename a subform, the subform control automatically renames its control source.  My users always see plain-English form name at the title bar because it is always the form's name by default; if I use cryptic form names like CustomerF, I have to manually rename the form's caption every time.  I could go on, but you get the picture.  I can get away with having free-form form names (and query and report names too).  Forms are what users use the most, and I really feel having plain English names for them is a benefit.  More user-friendly for them and actually less work for me.  And if another developer takes over my database, he won't be mad, because he won't see any form names (not many anyway) in the code.  The only form names he will see are the ones on the navigation pane.