1) Surround all constants by (parens), whether we'll be using them
     in a denominator or not.
  2) Express all time periods as products (24*60*60), not as multiplied-out
     constants (86400).
  3) Comments like "(60*60) /* one hour */" are as pointless as comments
     like "c = a + b; /* set c to the sum of a and b */".  Remove them.
  4) All time periods should be #defined constants, not given inline.
  5) All time periods should have doxygen comments.
  6) All time periods, unless specified, are in seconds.  It's not necessary
     to say so.

To summarize, the old (lack of) style would allow:

  #define FOO_RETRY_INTERVAL 60*60 /* one hour (seconds) */
  next_try = now + 3600;

The new style is:

  /** How often do we reattempt foo? */
  #define FOO_RETRY_INTERVAL (60*60)

  next_try = now + RETRY_INTERVAL;


svn:r6142