I'm occasionally asked how my campaigns can run for years with basically the same players playing week after week without everyone getting bored. I think there are a couple of major reasons why long campaigns have always worked for my groups.
First, my "campaigns" are different than what seems to be the common style today. Most people seem to use "campaign" to mean a series of adventures with the same characters with a "story arc" of some type. I run a sandbox, so I don't have a "story arc" with a beginning and end. There is always something new for the characters to do. While various activities do wrap up from time to time, the PCs allows have other things to do that have been "on-hold" while dealing with something else. There's never a place where everything is wrapped up and there is nothing left that anyone is interested in doing. Without this, there is no obvious place to stop playing and start another, different game.
Second, most players in my games play multiple characters. They aren't playing the same character week after week for years on end -- unless they want to, of course. Microlite74, like old school D&D in general, does not assume the characters in a party are all about the same level. The game works just fine with a wide range of levels in a party. This means that when a player is starting to get bored playing his fighter character, he can leave him or her in town and start a new character with a different class, background, and personality. My Sunday Wilderlands campaign has been running for over two years now and most players have several player characters, which one they play any given week depends on what is going on in the game and what they are interested in playing that week. We can always tell when one player has had a bad week, for example, because she always plays her combat-happy barbarian fighter who just lives to kill things instead of her scholarly magic-user after a rough week.
Multiple characters ties in with the first point as well. Characters can achieve their goals and retire from regular play without the campaign ending. This happened last Sunday. One character's reason to adventure was to recover his family's heirloom sword as its loss had saddled the family with a nasty curse -- no children born to the family would live past their first year. He found the sword a few weeks ago, managed to acquire it from its current owners, and last Sunday returned to his family home to a hero's welcome. The player is retiring this character as he's become the new head of his family and clan. Other characters, however, still have reason to adventure.
The ease of starting new characters at any time, means that it is also easy to work new players into the campaign when necessary. The sandbox style means players can come and go without disrupting the campaign. Without "story arcs", the campaign with not fall apart if a player with an important to the "story arc" characters has to miss a few sessions or even has to quit playing completely.
We are on Day 3 of our drive to collect money for the cancer fund and Karen's house as described in this post: Help a Former TSR Editor Keep Her House! The Final Episode. We've raised over $175 total so far. If you can spare a ten or a twenty, or even more, it will help so much. Karen and family can keep their house and I can pay for my wife's next CT Scan (coming up November 5th). To donate and help both Karen and myself, send a donation in any amount -- small or large -- via Paypal before 6am CDT the morning of November 1st. If you can't donate, good thoughts and prayers for Karen and her family are more than welcome. Please help spread the word to others who might be willing to help.