Possible Clues:

• That makes one week, but that's commonplace (8)
• As usual this doesn't happen each night
• Common or usual
• Common illness fellow avoided starts to die away in couple of years
• Familiar echo? Very, what diary regularly features
• Girl with light crosses track leading to common
• Girl and boy crossing yard, getting familiar
• Always three feet short? Yes, as usual
• Run-of-the-mill
• It's commonplace all year round perhaps