Over-hangs in prints I would like to ask this in more of a general sense than anything, just for people to make note.

I am printing out things for people and some files have some edges hanging out the side. I always worry, since it is printing in mid air, that it would screw up the print. But I was able to go, maybe 1mm(I am not to good with metric when it comes to guessing). My question is, how far at 90* from a wall can a printer pull off before it is necessary to have support? This would help me when slicing up files.
It is typical for a 3D printer to be able to manage one-half the width of the nozzle for unsupported layer printing. This frequently calculates out to a realistic 45° from the start point.

If you are getting 1 mm extension from a 0.4 mm nozzle you are doing well. It's possible that the layers are not strongly bonded at the point of extension from the vertical wall, but are then strengthened by the layers printed above, if they do not extend excessively.

If your part is designed well, the extension will be distributed gradually over more than one layer, allowing that 1 mm extension over 2.5-3 layers without impacting the appearance of the model in an excessive manner.

The above does not apply to bridges, as it involves a different dynamic for the printer/slicer software.