Border community needing assistance commonly when old (2,4)
I believe the answer is:
el paso
'border community' is the definition.
(city on the US border)
'assistance commonly when old' is the wordplay.
'assistance commonly' becomes 'elp' (I am not sure about this - if you are sure you should believe this answer much more).
'when' becomes 'as'.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'elp'+'as'+'o'='EL PASO'
'needing' acts as a link.
(Other definitions for el paso that I've seen before include "Texan city" , "City of Texas on the Rio Grande; aslope (anag.)" , "city on Mexican border" , "US city" , "West Texas town" .)