title: What is the difference between "datetime.timedelta" and "dateutil.relativedelta.relativedelta" when working only with days?
body: <p>What is the difference between <a href="http://docs.python.org/library/datetime.html#timedelta-objects"><code>datetime.timedelta</code></a> (from Python's standard library) and <a href="http://labix.org/python-dateutil"><code>dateutil.relativedelta.relativedelta</code></a> when working only with days?</p>
  
  <p>As far as I understand, <code>timedelta</code> only supports days (and weeks), while <code>relativedelta</code> adds support for periods defined in terms of years, months, weeks or days, as well as defining absolute values for year, month or day. <em>(remember, for the purposes of this question, I don't have to worry about hours, minutes or seconds)</em></p>
  
  <p>Considering that I'm only working with <a href="http://docs.python.org/library/datetime.html#date-objects"><code>datetime.date</code></a> objects, and only interested in periods defined by the number of days, what's the difference between <code>timedelta</code> and <code>relativedelta</code>? Is there any difference?</p>
  
  <pre><code>from datetime import date, timedelta
  from dateutil.relativedelta import relativedelta
  
  i = -1  # This could have been any integer, positive or negative
  someday = date.today()
  # Is there any difference between these two lines?
  otherday = someday + timedelta(days=i)
  otherday = someday + relativedelta(days=i)
  </code></pre>