Senescence

[busker]

Here at the end 
I’m fading into invisibility, ... a great opening
hardly taking a breath
that’s not filled with decades,
exhaling atoms of regret
that don’t even qualify as a sigh. ... only bits of the poem that come across as telling, not showing

I spend my day meditating
on a shorn winter field: ... nice
this is no way to go, the best way to go 
or simply another window-framed Nowhere, ... nice
I’m not sure which but sure
I’ll never know the answer.  ... I loved this strophe

Friends all passed on  ... 'passed on' - though it is probably meant as a genuine road-related metaphor here - sounds like a cliche. 
into a level distance that has no map ... nice
I cross and recross an abandoned road
looking both ways ... intriguing. Looking both ways to see who's coming and who's going? Lovely.
an obedient child of time. ... nice

A beautiful poem. I wouldn't change it too much, except the first strophe.
I like the conversational nature of the lines, perfect for the sentiment being conveyed.