Woah there, let's expand that story abit since you're getting the wrong idea about me being this heavy-handed rocks-fall-everyone-dies-with-my-temper-tantrum asshole of a DM. He had missed two and a half months of games, not just three. He missed 5, back to back. And it wasn't just him, it was his wife too. When he missed, she missed as well. She (was) new to our group, and she was not comfortable completely with us, I get it. So when they were gone, that party of 8 dropped to 6. When he reschedule we had two more that had to miss due to work, and one ended up being sick, valid reasons for missing, but his "I am too hung over" was not. We had 3 players and me, and I chose to pull the plug on the game because one was new, and her and her b/f are in an LDR (she visits on the weekends, and plays with us with her b/f during that time that she visits). I said to myself that I would rather give them back their Friday so that they could enjoy it as a couple, instead of having these awkward huge gaps in our game for a player's first time attending.
When he missed that game, and the other players who had to miss because of work found out, my entire group got livid with him and his SO. I had to do something, his (and his SO's) behavior had become problematic. I didn't take away his autonomy as a player in killing his PC. He had the ability to say he would attend more, but instead he said that he didn't think he could attend as regularly as was needed, and was fine with the consequences. I wasn't some tyrant about it, the decision didn't occur in a vaccum, he and I discussed it.
The game I killed him in he had been abducted by the BBEG. When the party failed terribly in some negotiations with him, it was a perfect time to off him. It worked out great for the narrative.
My point in killing players for lack of attendance is that, as a DM, you need to consider the rest of the group. This guy enjoys going out on Fridays, drinking in our local downtown, not hanging out with us and playing a game. For the rest of the group, especially the ones who have made serious efforts in attending, Fridays are best. We tried to accomodate him, and it didn't work. When I approach the topic of killing off a player, its because I've realized they just don't fit with our group and maybe I need to break that ice for them because they don't know how to say things just aren't working out. So I bring up their behavior, and what I am planning on doing. That usually means going our separate ways and killing off their PC. I wish they could work, but I would rather make room for players who want to be there than hold out hope on a player who's heart just isn't in the game. It brings the entire game down, and that behavior can kill games altogether. There is nothing malicious in my behavior nor in how things ended, he and his SO are always welcome back and can jump in as NPCs, and they both know they are welcome in this capacity.
As well, here are my incentive and attendance rules. All of my players are aware of these rules, they even helped me form them.
All players get one reroll for each game they attend. These rerolls may be banked up to 5 rerolls. The rerolls can be used on pretty much anything roll-based, including stats if they want to roll up a new character.
All players get a "loot token" for each game they attend which they may use to exchange loot of high value for something more attuned to their character (collectively we either agree to it, or it breaks the game and they don't get it). My players often make ellaborate backstories, so this works really well. Players can "outbid" other players for an item using more loot tokens. I usually have one or two "token" items per session that can be exchanged for something else.
If more than 5 players attend, then players get 1.5 xp for the evening. If the entire party attends, they get double xp.
If a player misses a game, they loose one reroll that they have banked. If they miss two games back-to-back, they loose their entire reroll bank. They never loose their loot token bank.
At 4 games missed back-2-back, we discuss removal from game. Obviously, this rule is flexible and legitimate reasons don't count towards this. We have one guy working in another state right now due to work. He will miss 8 or so games, but he isn't kicked out.
I've also changed the way players get skillpoints (we play pathfinder). Rather than getting all skill points at level up, they get them in increments equally divided by xp leading up to that next level. So, 2000xp for level 2, for 4 skill points, they'd get 1 skill point per 500 xp.