It's interesting how these things work out. I've been playing with my current Saturday Night group for about a year now. Initially I was a player in the group when we were playtesting D&D Next. When that didn't click for us, we realized we had a good core of a group with similar gaming tastes,and I offered to run Adventurer Conqueror King System for the group that remained.
Player turn over led to a few sessions of Ambition & Avarice playtesting using the Dwimmermount beta, which them led to a new campaign using AD&D 1e / OSRIC in Rappan Athuk. Four out of seven of us are from the D&D Next Playtest Group.
In addition, I'm in the process of "getting the old band back together" as one of my old players from high school and college calls it. So, that group would have roots going back nearly 30 years, even with a 16 year hiatus. We had our first session this morning, although it included only member of the 2nd generation of the old band (the MMO years)
How long have you been playing with your current group(s)?