Answer by Kavinay Kishor, Roman Catholic catechized as an adult
The last Pope to resign did so in 1415, during a time known as the Western Schism. There were up to three competing Popes at this point in history, and Pope Gregory XII relinquished his title in order for the Council of Constance to elect a new and legitimate Pontiff.
Pope Jean-Paul II was absolutely resolute in his final years about not resigning. Catholic theology regarding suffering is significant. In maintaining his role despite obvious pain and diminished capacity, Pope Jean-Paul II was clearly reinforcing key tenets of the church's dogma.
So yes, it's a big deal and a fairly significant change of precedent for Pope Benedict XVI to resign.
As much as I'm shocked by a Pope resigning, it's not an unreasonable action even if it is so rare. There have been many criticisms levied against the Roman Curia's handling of affairs when a Pope begins to decline. Both in terms of personal (Vatican healthcare is something that many still consider to be extremely poorly managed) and church interest (internal political disputes), a Pope has grounds to be concerned about his failing health.
What may not be immediately evident in light of the resignation announcement is that a papal conclave is actually a chance for change and reinvigoration within the church. Despite appearances, the College of Cardinals is not homogeneous. Just like the faithful they administer, they have different perspectives and concerns than one another. As a result, the most significant result of Pope Benedict XVI's abdication may be changes implemented by his elected successor.
Everyone across the Catholic spectrum has an interest in changes to church, one way or the other. The coming conclave is our best indication of how the church will react to both crisis and opportunity during a time of intense change.More questions on Catholicism: