Now I've done an IM... here is a little bit of feedback for those considering it, taking into account where I started from. I'm 43, in case that is of relevance.
Swim I started from nothing. I hadn't even swum 25m in a pool. Really don't enjoy swimming. It was just something that got in the way of getting on the bike. I am not very good at it, and just about pulled myself out of the water on time. Having said this, I have only had a few weeks opportunity for OW swim practice and the rest of my training has been in a pool. I found the two very different. I think I can improve, but not considerably, and the effort required to do so would probably not warrant the minutes saved.
Bike I didn't own a bike and hadn't ridden in over 20 years. I took advice from people on here and I found a Specialized Tarmac Pro on ebay for £850. I don't have aero bars, but I think I may use them next time on a flatter course. I found the bike quite easy to learn. Initially it was hard and I was struggling to do 15 miles in any kind of decent time. I was more like the village postie! My legs developed quickly though and soon it grew to 30-40 miles. Once I was up to 50 the gaps increased with ease to 70-80 and I did a few 100+ mile rides in training. I really enjoyed the bike and I think I can improve quite a lot on that with more specific training, more considered nutrition/hydration and perhaps some tweaks to the bike. I don't think spending big money on a new bike will be worth it though, for me.
Run I came to this from a running background having done some marathons, halfs and 10ks over the years. The running, therefore, has never been a problem. I just needed to learn to run after doing a bike ride and to keep it up during the other training. I did find that my running pace dropped because I was doing less miles overall, but my overall fitness increased. My mara PB is 3:29 but I would typically go round in about 4:00 (I did Paris in April in 3:55 for example). On the IM I did 5:35..! This is because I adopted a run/walk/run strategy. Clearly there is lots of time to be saved here if I try to run the whole thing, or just walk less..!
What did I learn from this...? Time for training is critical. You can't blag yourself round an IM. I found it soooooooo hard to fit in the demands of training with my life. It is easy to say 'just do it', but not so easy in practice. I did what i could and I did enough to get round, but of my 16 week plan I did perhaps half of the training specificied (and literally none for quite a few weeks!) and before that it was sporadic. I know I can do better - much better. Physically, I have a lot more to give. However, the reality of running a business and having kids is a huge hurdle that is not easy to ignore. I have thoroughly enjoyed the experience and I am so proud of my achievement. My goal was to get round, regardless of time, and I did. I will do it again and see if I can learn from this and do a little better next time.
The Pirates are the best..! Superb bunch of people and the experience would have been far less enjoyable if I had done it on my own at a non-pirate event.