I use them when i manage to make a plan, just to make sure i dont forget the plan before i have a chance to continue the game. Sometimes there are days between moves in a game.
Are Conditional Moves Really Necessary?

If the person I'm playing is online, and we're both making moves, I don't use conditional moves. However, if the other person isn't online, and I've spent a lot of time thinking about my move, and the possible lines that may result from them, I make sure to set the conditional moves, otherwise, by the time I get back to that game (it may be a while as I'm often busy) I'm liable to forget what I was thinking and make a completely different move than I had originally planned. Because of this, I often set conditional lines for almost any possible move my opponent may make (so I don't have to try and figure out the same thing twice).

I think conditional moves in correspondence games makes perfect sense because people often are just consulting the most recent opening theory. So why waste time in the opening if both players are playing out of a book? Just get to the middle game and let the game begin.

I hear your point Billium248, but hear this point out.
If I run through a sequence of moves in a particular game, then I have to go to work or (insert some life event here) when I get back to the board on any of my games, I always play back the last 5 or so moves leading up to my move.
Its pretty difficult to forget a solid continuance that one thought up prior to the disruption. Or, I may again be making assumptions here. Its why I raised the question.
My take on it is that when opponents play conditional moves on me, I sort of feel like they are trying to rub it in. Like "the jig is up" sort of thing.
I don't absolutely hate conditional moves(and have been guilty of using them in the endgame at times), but I kind of agree with Fonix on his general point. What is the rush? If you are having to wait for people to make their moves just sign up for more games. I promise it will take care of the problem. Or take advantage of some of the articles, tactics trainer, etc. while you wait for your opponent to move. This is a game of leisure is it not?

I always run back thru the last few moves when I return to a game too, Fonix. But there have still been a lot of times that I've found myself making a move where I said, "Now I said I wasn't going to make that move for that very reason. " Conditional moves helps me avoid these problems (of course sometimes, I think I can make THEM too quickly too
).
I understand that some people view these conditional lines as "rubbing it in" or whatever, but it is NEVER my intention when I make them. I try hard not to make my lines very long for this very reason. Because I know I'm not trying to assert my "superior foresight" when I set up conditional lines, I never assume that my opponent is doing so when I encounter them used against me.
Here's one of my favorite jokes that seems appropriate for the situation:
Why do us blondes only get a half hour lunch break?
Cuz if you give us a whole hour, you have to re-train us.

Cuz if you give us a whole hour, you have to re-train us.
LOL,
Thats just too funny. And I get what you are saying. Thanks for shedding light on the other side of the equation for me mate!

Yes ! I think stallers really must hate conditional moves and that alone is reason enough to have em !

Or am I simply making lame assumptions about the way people ought to approach this game?
Yes.

Are they necessary? No, but neither is Chess. They are a convenience. When I receive a conditional I have the same amount of time to reply as with any other move so it doesn't bother me at all. But I never submit conditionals here at chess.com because I don't find the method to be very convenient. There is another website where I play that has a very convenient method of submitting conditionals and I submit conditionals there whenever I feel like it's a good idea. At that website there is no notification that your move has triggered a conditional. The game simply reappears on your list right away.
I really think this is a stupid question. If you don't like conditionals then don't use them. And I certainly hope it doesn't trouble you too much if they are made available to those among us who like to use them. If you don't like spelunking then stay out of caves. Is spelunking really necessary?

I don't use conditional moves often. However, they are very useful when (1) I think that the number of likely continuations is very small, and (2) my opponent doesn't move as often as I do.
I see that the OP has over 100 current games. I prefer to have a few games and finish them quickly. With too many games going on, they no longer feel like games to me. They feel like a bunch of position diagrams. I'm sure there are benefits to both approaches, but I enjoy the organic feel of a game where I can easily remember the position and its history and my plans and concerns.

Conditional moves arent necessary, no. However, they are helpful/useful to many players. I can see how conditional moves could be very irritating to people with too many games going though !

Rubbing it in? Let's not be so sensitive, anything to move the games along. I second what Pegrin said.

They're extremely useful, however I tend not to use them unless I have a very clear line mapped out and I've examined it thoroughly (most frequently in clearly won endgames against stubborn, non-resigning opponents). The only reason I don't use them more is because I try to make a habit of re-examining each position with fresh eyes after every one of my opponent's moves even if it's down a line I'd envisioned a few moves back. There's always a possibility that I missed something I'll catch later and entering the entire line as conditional moves doesn't afford me the opportunity to remedy those misses.
The only real valid argument I can think of against them is that they would make it difficult for someone to turn their vacation mode on because of the requirement to have made moves in all of your games before doing so (not an issue for premium members, mind you).
I think that a simple fix for this might be to let the users turn their vacation time on without having made moves in all of their games, but only stop their clock after they've made a move. That way the conditional move would immediately return them to a position where it's their move but their vacation is on for that game.

I wish they would implement the " if any " into conditional moves too. This was a feature of real correspondence play as well.
The title sort of says it all.
I get that some people can see the continuance of a particular game, or a particular line, but why the rush? Maybe its just me, but it seems a bit pretentious to submit conditional moves. What I'm trying to say is that no one should be in that big of a hurry to finish a game. Right? Or am I simply making lame assumptions about the way people ought to approach this game?