It has that funky runners smell

Grubbies:

Old or distressed clothing one wears in an environment that may be dirty or wet but that does not merit use of coveralls or protective gear.

I forget how old this top is but it's my favourite. It seems as old as me, a New Balance long sleeve number in red and black. I'm not sure of it's exact vintage but it has that funky runners smell that never quite washes out and the sleeve ends are frayed. The zip sticks and it has no pocket but I love it. 
I think most of us have our favourite bits of running kit, comfortable old friends that we trust and know. By contrast, I have gear I've had for a while but hardly worn, it lacks soul, it never quite relaxes.
The best stuff we wear until it becomes threadbare and falls apart.