How do you use your garmin in a tri

It all depends,

I only use mine in the run since I have a different computer in the bike. So I leave it inside my shoes pick it up start running then put in my hand, I would get signal before getting into mile 1, so I just lap it in mile 1 and then I continue mile by mile.

Same. For some races, I will only wear my old school Timex Ironman, because I only care about the time. I have a bike computer for all data on bike and I know my running time splits and mile markers every mile in most races. I don't need my HR data in a sprint or Oly because I already know it's high. So, even though I have a Garmin, I use it mostly in training and keep it simple on race day.

I just use it on the run.  Leave it in my running shoes.  Some races require you to drop off run gear the night before so in those circumstances it is kind of a pain waiting for the satellites to synch up after putting it on.  I've been half a mile into a run before it kicks in.  At shorter races, I turn it on as I leave transition setup before the race.  I have it set at half mile alerts for time so use it primarily for monitoring my pace.

I used it in a marathon last month and kind of spaced on the first split.  Went past the one mile mark and thought that's odd I didn't get a split.  Looked down and saw I was 1700 yards into my race.  I had just come back from vacation where I did some open water swimming and forgot to put it back in run mode.

I use it as a paperweight...

Joking of course, but honestly, I tried it a couple times and it's more trouble than it's worth.  Ended up screwing up pushing the buttons or using multisport mode plus mine was not waterproof.

I found using my regular IM watch/HRM is better.

I train with the gps all the time.  Never race with it.

x2

I have the 910XT and use it during the entire race.

Push "start" when the gun goes off.  Push "lap" in T1.  Push "lap" in T2.  Press "stop" at finish line.

It is that simple.

I have the 210..same issue as you.  In my first tri a month ago, I turned it on, acquired the satellite fix, and started the timer...then I left it on the bike and headed off for the swim.  When I came in from the swim, I hit the lap button to start the bike segment.  Everything was going well until my newbiness reared its head at T2.  I forgot to take it off the bike.  I did remember to take off my helmet!  Had to run the run by feel.

This. same process for the 310xt

I run with the FR110.  I keep it in my running shoes, power it up as soon as I'm messing with my running shoes in T2, and put it on as I'm running out of T2. Just remember to reset the prior run's data beforehand.

I have the Edge 500 on my bike.

I know the 910XT is a nice convenient multi-sport watch, but didn't want a laptop on my skinny wrists.  I anyway already had the FR110 and like it, it's my every day watch as well.

I wear my Garmin 910 for the entire tri, swim start to run finish.

Although, I have an indoor swim triathlon this weekend so I'm not sure if the Garmin will pick up satellites.  In this case, I will just use my regular bike computer and my timex ironman. 

...unless you check "Include transitions"...then it is:

Push "start" when the gun goes off.  Push "lap" going into T1. Push "lap" going out of T1.  Push "lap" going into T2. Push "lap" going out of T2.  Press "stop" at finish line.

I use the 910XT for the entire race. I set the watch to "Multi-Sport". I hit start; the lap button in and out of transitions; and stop at the end of the race. My biggest problem is forgetting to hit the lap out of T1...

^^^This^^^ I use my FR910xt very differently than I used my FR305.

What model are you asking about?

+1, I used the "multisport" mode in my last race.  Garmin worked great, but I gotta get used to switching it coming in/out of transition.  According to my Garmin 310XT I had a 5+ min T2

Yep, it's stuff like that made me stop using it.

One time I had a good swim, fast T1, a 5 second bike leg, 3 hour t2...

I mean, the reason I wanted to use it was to have all the data at the end.  But if you skip a button, or press it twice in the rush of transition...  Then it doesn't load into training software well and it's of no use.  I think I tried using it 4 times and only once got it right.

Another time I had it waiting on my bike all ready to go.  Get there after the swim and it turned itself off.  So had to turn it back on, wait for satellites....  I kept on racing, but it was a couple min into the bike it finally was working.

To me, my Timex HRM and bike computer give me all the information I need.  HR, speed, laps.  Run pace I can figure out pretty quickly just doing the math from aid station to aid station.  I guess I found myself too concerned/worried/focused on if my Garmin was working correctly, or be upset during the ride if I forgot to push the button and it didn't put me on the bike screen showing speed/cadence and stuff and obsess about it during the race.  There was more important things to think about and any additional stress during a race is counter productive.

I have the FR305.

I put it in my swimcap before the race in multisport mode.

T1, I hit lap as I pull off my cap and grab it.  I throw it onto my aerobars.  I Hit Lap as soon as I get on the bike.

In T2 I pull it off the aerobars and start running with it in my hand.  I hit lap as I start the run and then put it on my wrist..

These are the kinds of results I get:

http://connect.garmin.com/activity/202063332 

http://connect.garmin.com/activity/202063336

http://connect.garmin.com/activity/202063341

Dude, Now I am impressed.

Max Speed: 1,480.8 mph

Did the sonic boom disrupt the race? :-)

KISS - Keep It Simple Silly.

That is why I don't do the "include transitions" mode.  You complicate matters exponentially by having to hit the lap button twice in each transition.  All my races give me T1 and T2 splits, so I don't need the Garmin to do that.

If you "exclude transitions" then for all intents and purposes, you only have to hit buttons twice during the race (once in T1 and once in T2).  You press start (immediately) before the race and stop (immediately) after the race.

I like including the transitions that way I can see the actual time it took me to swim vs the time it took me to swim plus the time to run between the water and the timing mat.. of course I've only done two Tris and I didn't use multisport for the first.. but then again it doesn't take me that long to change the mode on the watch and I can do it while biking or running if I mess up.