My RP club has been going on for many years, which has the unfortunate effect of us getting older. Many members of my club have started to acquire a 'real life', with more of their time devoted to partners and new families.

I am currently GMing multiple games, and I have the constant problem of my players phasing in & out of existence like a pack of blink dogs. What is the best way of running a game with a constantly unreliable group?

So far I tend to carry on with the game if a few members don't show, but avoid major plot points or big fights. I also try to throw in some side-quests, which seems to be a good way to slow the party down whilst keeping momentum going. This approach seems to mess up party xp though.