Unless the roof edge is quite uneven some shingles overhang significantly more than others it should have the same stickout all along.
How much should a roof overhang a gutter.
To create a cantilever properly you will need to know plenty about physics like torque and rotational equilibrium.
The bottom tile or slate of the roof covering should project at least half way into the gutter the ideal distance is between half way and two thirds of the way over.
A typical metal roof overhang may be 2 to 4 inches or even less.
Each has their own reasoning for a slightly different amount of overhang.
Too much overhang and the shingles could blow off in high winds.
Metal is usually installed on rafters or strip sheathing rather than the solid decking used under other materials.
You can add 3 to 5 inches to the top.
Shingle manufacturers say to use a 1 4 to 3 8 inch shingle overhang over the eave where your roof ends.
The brackets typically hold the gutter about 1 2 1 inch away from the fascia board if u type brackets otherwise if screw through type the gutter might be almost up to the fascia board.
We ve seen other references that suggest extending the shingles a bit more than the manufacturers suggest to compensate for wavy eaves but they do not indicate extending more than 1 inch over the eave.
Greater overhang becomes a point of leverage for gusts of wind to rip off your roofing.
Here phil explains how much overhang a roof should have at the gutter.
This will keep rain away from your shed.
The reason for this is that whenever rain runs down any type of roof when it gets to the lower edge it clings to the tile or slate by capilliary action this means that the water actually runs around the bottom edge and slightlly back up the rear of the tile before gravity allows it to drop into the gutter.
About 1 inch just enough to assure the water goes into the gutter and not behind it.
Too little can allow water to seep into rake or fascia boards.
Anywhere from a 1 2 to a 1 overhang is acceptable as you can tell from the varying comments amongst the previous posters.
In my opinion the shingles should never be exactly even with the edge of any drip edge flashing.