It depends on many factors.
1) Blind levels, are they small, are they big, are the blinds at the mid stages?
2) Your stack size compared to the blinds (I.E) How many BBs you have left?
3) The type of players with you at the tables? Are they passive/stations? Are they overly aggressive? Do they just "Flat", do they "3bet/4bet on a continual basis"?
4) The position of the table?
5) Your Image? By opening, will you get respect? By opening do they think you're just "Opening because (You're just opening)?
So answer Is It really depends