Most Useful Complication For Modern Life

My personal prioritization:

1. Calendar 
2. GMT

....

....

199. Diving Bezel

200. Chronograph (but looks great)

People actually use their watches???

Half the time, I don't even bother to set my watch!  

This is what I use all my complications for...

For me, date and dive bezel are the most used and appreciated. I use chronographs quite often too. I appreciate GMT, but have little use for it 99.9% of the time. For a full calendar and moon phase data, I'd rather use a phone.

Complications are used to explain the complications to people who could care less.

Don't have a watch with a diving bezel anymore, but used to use the pip as a pseudo alarm.

With the globalization of trade & commerce, it's the GMT. 

I have no idea why they appeal to me so much, but I really like chronographs. I end up using mine regularly for things such as timing wait times, timing how long it takes me to do Sudoku puzzles, tracking billable hours, identifying how long it takes for the edibles to kick in, etc. I also really appreciate that they provide opportunity for interaction with the watch above and beyond simply winding and setting the time.

Nope. Not at all. Never moves….My diver bezel stays put :)

It’s too sexy to move.

When doing those "if I could only keep 2 watches" thought exercises, I end up with a pair of no-date divers.

No question for me.

1. Date
2. GMT
3. Chronograph

Date is my number one, but a dive/timing bezel is number two. I use the bezel for timing lots of little things like cooking, meetings, etc...  

Calendar and moonphase, obviously. The rest of these are novelty gags. Furthermore, day, date, and moonphase is actually horologically significant. GMT may be as well, but that's for airline pilots, as anyone else can just do simple math instead.

Many times have I worn a dive bezel or chronograph watch in anticipation of using the feature that day. The need, even the want, just is not there.

People that poo-poo moonphase as silly ornamentation need to get outside after sundown more often.

I find bezel a little better for timing things than Chronograph.

Used to travel globally a lot and can see how a gmt would be perfect for that.

 moonphase is pointless but so cool

 Date is probably the most useful but dang - no date is sexy.

Andy Warhol in the house 😂

Yeah I love Chronos too, partly the case aesthetics, partly for timing heart rate 👍

The Sinn 240 State-of-the-Tide complication, obvs. Must get one of these.

I know that digital stuff probably doesn't count as a complication, but the countdown timer on my Casio Royale is really useful. I leave it set at 3m50s, so I can make a cafetiere of coffee, put the lid on, start the timer, and plunge it at 4 minutes exactly. Chrono or dive bezel aren't so good, as without the alarm I'll just forget and over-extract the brew 

I'm a simple man who collects simple watches.  Don't dive, don't travel that often, but sometimes I do forget what day it is.  I'll take date only, just make that window bigger for my 58 year old eyes.

I found my Glycine Airman to be really useful, since I'm in contact with a buddy in Louisiana, which happens to be 7 hours behind Warsaw. Oh, and the date comes in handy as well, when I'm filling it in on some paperwork at work.

The Airman's not strictly what you'd call a GMT, which usually means a combination of a standard 12-hour display and an additional 24h hand. However, the Airman was introduced before the GMT-Master, in 1953, and was the first to feature a 24h rotating bezel for monitoring a second time zone.

I use the Chronograph function to time sth in the kitchen, laundry, time I spend grocery shopping etc. I love to interact with my watches. So the Chronograph function is my favourite by far. 

Have and use watches with A, B, and C.  I use the dive bezel and chronograph to time things/events.  And the GMT comes in handy on days I know I need to know the time in another part of the world.  Don't have a watch with D.  Would love to have one though.  

I use my diving bezel to time my breaks at work

My most used complications are similar to many of the comments above. 

1. date 
2. alarm - just got my grandfather’s SEIKO Bellmatic and dig the alarm on it. 
3. GMT - I work with folks in other time zones. 

dive bezel - fidgit spinner, work anxiety is real man. 

The diving bezel is essential, for cooking Al dente pasta.🤣🤣🤣

Chrono every morning to time my siphon brew coffee. 
 

Caller GMT to keep track of my girlfriend when she is home visiting folks in Brazil

Diving bezel to time my laundry 

Not me lol......I still like them ..

With my handle how could I select anything other than "B"?

First of all, fidget spinners are important. 
 

Secondly, I have family in different area codes so I like having a caller GMT. 
 

I would have said dive bezel since I do actually go scuba diving and I like to time things, but I routinely use other instruments for those activities. 

All of the above……

Use diving bezels on my watches to time things sometimes around the house. Date is nice to have and helpful at times, but calendar and moonphase not so much. 

I have several chronographs, the number of times I have seriously used it is in the single digits over the course of 15+ years. Not useful for me.

I don't have a GMT, but I do not travel, so not very useful in my case. Might still get one in the future to try it out (Longines Zulu Time is my top choice) and just complete my collection.