Lesson: After securing a sweet parking spot right by the marathon finish specifically for a speedy egress, don't leave the keys with someone (who doesn't run) while you run the race. My girlfriend at the time took the car to go shopping (when she could've walked to downtown) and didn't consider what Austin, Texas traffic and race day parking would be like. I pushed hard enough to PR, but had to wait about an hour for her to show up and then walk at least 2 more miles to where she parked my car. Illegally. So I had a ticket too. ("It's not that far! You just ran 26.2. You can walk a few more! But I got a sweet deal on some shoes, had a nice brunch, and read my book at a cafe.")

In my 1st tri last year, in my haste to get out of T1 quickly, I threw my wetsuit down on top of my running shoes. Came back from the bike to...soaking-wet running shoes!

Good advise on that sponge! I love the idea of it but there has to be a better design! Every ride I take, my bike (and sometimes me!) is covered in sticky gatorade. Yuck!

I don't think the Aerodrink was designed to be filled to the absolute top. I've never had a problem with mine, sponge or no sponge, but I also don't fill it all the way up. By the way, there is now a better design...the Aquacell:

http://www.profile-design.com/products/hydration/aquacell/

(I am not affiliated with Profile).

I don't normally have an issue with it if I take time when inserting the yellow mesh thing - l just roll and twist it before putting it in place - but for a race - I will take an additional precaution (especially seeing the IMWI course littered with them) - So I drilled a small hole on either side of the opening just below the lip - then put a zip-tie through one hole and worked it through the yellow thing and then finally out the other hole and finally secure the zip-tie.
Keeps everything in place so no worries come race day.
Then just cut the zip-tie off off to wash - and zip-ties are cheap.

In my first race (CapTex 2005) I thought I would save some money by wearing my jammer style swim suit instead of buying specific tri shorts. They look about the same right? Everything went well until after the race my wife informed me that my butt crack was clearly visible through the now worn out shorts.

Don't be cheap. Buy some tri shorts.

I learned it's detrimental to practice swimming in your wetsuit before you wear it for the first time. Right before my first triathlon of the season last year and my first in four years, I prepped the suit by soaking it in water to get it to stretch better as suggested by a teammate. I also listened to the fact that you have to roll more to swim in a wetsuit. However, I didn't practice in it before the race. Race day I put on the wetsuit and did a quick warm up. Did it with my head above water just to see how stretchy the suit was. Pretty good, I thought. As we started the swim I began to hyperventilate because I wasn't used to how much the suit compresses your body and more importantly your lungs. Ended up finishing the swim, but only after I took off the wetsuit about 50 yards in and gave it to a kayaker. Pretty embarrassing. Unfortunately, I didn't learn anything, since it happened at the next triathlon I did. I didn't swim in it again before the next tri as I had basically given in to ignorant bliss. I had embarrassed myself a second time at my first HIM. After that I started practicing in it and conquered my wetsuit issues.

At one point, I was worried that I would never be able to compete in a HIM or IM, my ultimate goal, because the swim freaked me out. Thank god it worked out!

Make sure you vaseline your race shoes in the hot spots. Completely forgot about it, as I have been racing with the same shoes for a while now, so it hasnt been a concern. Well, new shoes, rushing around the morning of the races, forgot to prelube. 2 nasty blisters- one of the arch of left foot and a bad one on the heel of my right. I could tell 1 mile into the run that it was gonna suck.

Showed up at my first tri wearing board shorts, no wetsuit, and never having swam in the ocean (unless bobbing up and down 10 yards from shore on a boogey board counts) and only having spent in the pool at the occasional backyard bbq parties.

It was just a 1/2 mile swim leg but it took me 44 minutes to get through it. I was second to last in my AG. I can't believe I beat someone!

My last 1/2 mile sprint swim took me around 16 minutes. So I've managed to shave some time since then.

So I'm finishing up a 25 mile ride yesterday, cruising on with with about a 1/2 a mile left to go. I've worked pretty hard, but not too heavy, so I'm slightly tired, but not wiped. As I'm traveling down a relatively busy road, there's a weird rubbery sound from my back wheel, and suddenly, wham its like my brakes went on for no reason. Weirdly, pieces of rubber go flying past my face and I'm thinking holy cow must I have just had the blow out of the century. I'm literally bracing for the fall, expecting to feel that fish tail, hear the metal grinding then then the bitter sweet taste of pavement (which my now hyper brain identifies as particularly rough).

Instead, I come to a quick stop, very controlled, but something is clearly wrong...

I look down... Wheel is intact, but there are pieces of inner tube everywhere... then I see it.

On my saddle back, there's an elastic loop, and an elastic band that's meant, I believe, to hold a spare tube. I hadn't secured it adequately, and well, it fell out, and wrapped itself around both sides of my rear axle, then stretched and got shredded. It was wound into my cassette, and around both sides of the axle. It was relatively easy to fix, but thank goodness the stem hadn't gotten into the cassette. Somehow that was avoided.

Lesson: Don't leave an inner tube in that strap without making sure it can't fall out.

I was lucky I think that I didn't go down, so all in all, I guess an easy lesson in the grand scheme of things...