Squeeze the side of the avocado, and if it gives AT ALL it's ready to eat.
If it's soft it's way way overripened. Take a piece of cardboard between you fingers and squeeze - that's the firmness level that indicates the avocado is ready. Actually even more firm than the cardboard and the avocado is still ready.
> where you can sometimes feel the level of hardness/softness more accurately (if it is a particularly thin-skinned one), you bruise it
If it's soft it's way way overripened. Take a piece of cardboard between you fingers and squeeze - that's the firmness level that indicates the avocado is ready. Actually even more firm than the cardboard and the avocado is still ready.
> where you can sometimes feel the level of hardness/softness more accurately (if it is a particularly thin-skinned one), you bruise it
You are squeezing way too hard.