Converts a duration (in seconds) to human readable. A bit crunky, and doesn't work that well.

approx_duration.php

<?php

function approx_duration($duration,         // time period in question, in seconds
                         $short=false,      // single letter suffices (m=month and minute!)
                         $roundupdown=true, // round up/down rather than just down
                         $keepdays=false,   // largest division is days, not years/months/weeks/days
                         $keepzeros=true,   // keep (and count) zero values
                         $cutoff=2,         // maximum number of fields
                         $blankzeros=true)  // even if $keepzeros for cutoff, eliminate from display
{
  if($keepdays)
    $periods = array('day' => 86400,
                     'hour' => 3600,
                     'minute' => 60,
                     'second' => 1);
  else
    $periods = array('year' => 365*86400,
                     'month' => 30*86400,
                     'week' => 7*86400,
                     'day' => 86400,
                     'hour' => 3600,
                     'minute' => 60,
                     'second' => 1);

  $buf = array();
  $count=0;
  foreach($periods as $period=>$unit) {
    if($duration<1) break;
    $x = $duration / $unit;
    $x = $roundupdown ? round($x) : floor($x);
    if(($keepzeros and $count>0) or $x or (!$buf and $unit == 1)) {
      if($short)
        $buf[] = $x.substr($period,0,1);
      else
        $buf[] = $x.' '.($period.($x!=1?'s':''));
      $duration -= $x*$unit;
      $count++;
      if($count>=$cutoff) break;
    }
  }

  if($blankzeros)
    $buf = preg_grep('/^[^0]/', $buf);

  return join($short?' ':', ', $buf);
}