I usually have 8-900 km in pair of shoes...

After 100 km I measure the sole depth and when it is 10-20 % less - usually 3-4 mm after 8-900 km - I start looking for new shoes...

Very unscientific... but it works for me :-)

EDIT: By the way: Basically I use a normal ruler. I put in inside the shoe and measure the hight to the next shelf in my bookcase... Easy :-) I do this every 100 km or so. (I'll see if I can make a picture next time I do it)

I usually have 8-900 km in pair of shoes...

After 100 km I measure the sole depth and when it is 10-20 % less - usually 3-4 mm after 8-900 km - I start looking for new shoes...

Very unscientific... but it works for me :-)

EDIT: By the way: Basically I use a normal ruler. I put in inside the shoe and measure the hight to the next shelf in my bookcase... Easy :-) I do this every 100 km or so.

Note that I usually apply a little bit of pressure on the ruler to make sure my custom made insole in properly positioned.

Also I don't measure anything the first 100 km to allow the shoe to "settle in" first..

I usually have 8-900 km in pair of shoes...

After 100 km I measure the sole depth and when it is 10-20 % less - usually 3-4 mm after 8-900 km - I start looking for new shoes...

Very unscientific... but it works for me :-)

I usually have 8-900 km in pair of shoes...

After 100 km I measure the sole depth and when it is 10-20 % less - usually 3-4 mm after 8-900 km - I start looking for new shoes...

Very unscientific... but it works for me :-)

EDIT: By the way: Basically I use a normal ruler. I put in inside the shoe and measure the hight to the next shelf in my bookcase... Easy :-) I do this every 100 km or so. (I'll see if I can make a picture next time I do it)