EDIT of this post:
My birth year is 1937 and I turn 78 today (4/7/2015). Our original core group of 9 guys all grew up together and we are all within a few years of each others ages. Two of our original 9 have passed away and of the remaining 7 only three of us are in good health. Out of the original 9, 4 of us still live in the same neighborhood and play regularly. The other 3 still show up about 4-6 times a year, but due to declining health those three have not been able to make it this year and the four of us that game together regularly are planning a trip to visit each of the three that live out of town. One of the four of us is also in poor health but determined to make the trip.
We started an organized twice-weekly game night in 1956 playing cards, boardgames, and wargames that we made up. We had played together from early childhood (cowboys and indians was a long time favorite), we were into westerns, fairy & folktales, science fiction and a lot of other things. I remember homemade bow & arrows, spears, swords, staffs etc., and hunting and fishing with our fathers and grandfathers, and getting old enough to get our first guns and the thrill of hunting and getting that first kill.
Starting in 1956 (noted above) up until 1971 we had played about 1400 games. Then in early April 1971, a cousin of one of my friends sent him a copy of the Fantasy section of Chainmail. We got hooked on it quickly and played it right up until the same cousin sent a copy of D&D in February 1974 and we immediately converted our Chainmail campaign over to OD&D.
Starting with Chainmail Fantasy and continuing with OD&D we played our 1000th games in January of 1982, our 2000th in December 1995 and our 3000th game in September 2008 and this past weekend April 4th and 5th we played our 3687th and 3688th games. Our current goal is to reach 4000 OD&D games and 400 years of game time.
We have played through about 371 years of game time in the main campaign and have four OD&D side campaigns in the same world. I call the main campaign the Tarrozian Campaign and it is very deadly. TPK's are common and getting a group of characters to 4th level is always a cause for celebration. The original core group of players have had between (I am guessing here) 550-750 characters each. In spite of about 450 TPK's, each of us have retired about 10-18 characters apiece. But on some game days we have went through 8-10 characters each.
Our typical gaming session used to be about 12 hours in length which works out to about 36 days of game time on the average. (includes travel time and in-town time which usually passes very quickly, most but not all the time). Ten game sessions is roughly a year of game time, and we usually go through about 7-8 game years per year, although once we retired we are picking up the frequency of gaming so that is approaching 10 game years per year for about the last 12 years. On the other hand since we passed about 70 years old the length of our games has decreased to about 8 hours split into two - four hour segments with a long break in the middle.
A surviving character will usually reach 4th level in about one game year and 6th level by the end of the second game year. By 4th level a fighting-man (as an example) would have a magic weapon, a 50% chance of magic armor, some other magic item and would have saved about 2000 GP after all spending etc was accounted for and would have that amount available to outfit his next foray into the wilderness or a dungeon or whatever. By 6th level a fighting man would have a magic weapon, magic armor, 1 or 2 other magic items and have accumulated about 8000 GP. He would also have attracted the first few of his permanent followers by this point based on his Charisma.
The odds of a starting 1st level character reaching 4th level is roughly 1 in 6. The odds of a 4th level character reaching 6th level is roughly 1 in 2. The odds of a 6th level character reaching 8th level is roughly 1 in 2.
Survival is tough, magic is hard to come by and special, my players seem to like it this way and when I play I like it this way as a player.
We have some children who play now and then and some grandchildren who play now and then. We also have a few great-grandchildren who are just starting to play. We hope that some of them will carry these campaigns on when we are gone.
Update: As a result of the recent interest in this post I will be adding additional posts about the campaign world and game to the blog and to my section of this forum of which I am a member.