Hate to put a hole in that wall and then stand back and realize the painting should have been a little higher or lower?  Ever buy a dining room table and get it home to find it is too large/small or just doesn’t look right?  Ask A Designer tips from House and Home suggest:

Art should hang 60 to 66 inches from the floor to the center of the art work.

Position the bottom of a fixture 32 inches to 36 inches from the top of the table.

Chair rails should be mounted 30 inches from the floor.

And choosing a dining room table that fits?

Allow 24 inches of space for each person seated at the table, leave at least 2 to 3 feet between the backs of the chairs and a wall so the chair can be comfortably moved in and out.

A round table is good for square rooms.  36 inches wide to seat 4, 54 inches wide to seat 6.

A rectangle table is good for most rooms.  A 40 x 72 inch table will seat 6.  A 44 x 80 inch table will seat 8.

An oval table is good for wide rooms.  47 x 78 will seat six guests.