Restarting old games — whether to and how

That's restarting as in a car, though one could have written revive, to avoid the sense of reinitialise.

Ignoring essentially stillborn games, in my experience games falter most often for one of two reasons. The most prevalent is that the game mechanics have given way under play; restarting means porting to a different system, in which characters don't work like they used to, and it soon needs to be put out if its misery (after seeing it happen a few times, we stopped doing it).

The other is that some of the players — often the GM — can't get out enough to justify what is being put in. This may manifest as the thread getting lost, perhaps due to pushing past a logical stopping point, or an acrimonious terminal session where divergent goals can no longer be smoothed over. In this situation, admitting that this is dead, and burying it is the only way.