I say call mia when you can. Sometimes you are too busy, or the person is at the store, or you just died etc. Pings are also useful.

this is the funny thing... dont call mia your just as at fault if a teammate dies and/or feeds off your opponent as the player that has 0 map awareness.... call mia and its all they're fault for not heeding your words/pings and they have no one to blame but themselves

I'm with the Con Mia group for many of the reasons already listed by the comments. However, when in vent or skype, I do often call them out since it doesn't slow me down from gameplay but only if I know there are people playing with me who are less experienced or just simply lack the map awareness. I guess I'm a bit of a hypocrite and/or just selfish with people I don't know.

My account is level 26, and the ping helps me the most. I understand that more experienced gamers will doubtlessly have more map awareness than I do. There has been more than one instance when I made the mistake of focusing so much on my laning that I forget there's a whole game happening around me, and I can get out when someone draws a line with 3 pings to indicate the movement of a gank.

I can say from my experience that it saves newbies like me. Being reliant on them is a bit embarassing for me, so I think that I'll be a better gamer for it eventually and not one that relies on these indicators indefnitely.

my 2 cents, in this game, notifying your allies that your opponent is missing is very helpful, but take your hand away from your controls just to type MIA could make you vulnerable to attacks.

more than once i've had incidences where I would type out mia and the enemy turns out to be in the bush waiting for me to over extend and as im typing they come out.

now since im typing, im not longer able to cast spells or anything until I hit enter. just not worth the risk most of the time

pinging the map and using the right pings I find the best way. this keeps you from moving your hand away from your controls, and its quick and easy, but you must use the right ones. alt+click for attacks and V for retreat. I cant tell you how many times my allys would use the alt+click ping to try to notify me theres someone there and we mistaken it for attack that target. communication is key in this game

what this game really needs is voice chat, that way you only need to press a button to turn your chat on and this would allow you to call out mia instantly with absolutly no loss in control.

so to wrap it up, calling out MIA in chat is a deadly gamble, pinging the map with the correct ping is much more useful, if voice chat finally makes its way into the game, only at that point will calling MIAs be necessary

I found calling MIAs more necessary at lower levels. I just hit level 30 and it's generally not necessary any more, but I do it when it's obvious they went to gank.

I don't think it should be expected of every player, but it is a team game at the end of the day, and you and your team are only going to win by working together. I'm only a new player but I know I try to call MIAs as often as possible because the last thing I want is a teammate dying when I could have told everyone that my opponent wasn't in lane.