Old habits die hard and sometimes not at all, but if you want to see improvements in your performance or make the leap from recreational athlete to ultra-competitive pace-setter, you must address any triathlete transgressions quickly.
As my gym teacher used to say, it's not practice that makes perfect, it's perfect practice. Allowing bad technique, poor nutrition or careless organisation to become a habit will result in anever-widening gap between your potential and your results.
With the help of some of the country's finest athletes and a sports scientist, we've come up with a list of the most common training and race-day misdemeanours and the tips you need to tackle or avoid them. These people have experienced them all, so now you don't have to.
Not keeping a training diary
It's a simple task that can offer huge benefits, so why aren't you keeping a training diary?
"It's vital, but it requires discipline," says triathlete Jenny O'Brien, who has represented Britain at the World Triathlon Championships in the 25-29 age group. "Use it to plan a season of training sessions and races."
It also allows you, when you are not racing well, to look back at a time when you were performing better and see what you were doing right. "You don't have to write much; just what type of session it was, your splits, how you felt, what you had to eat, and other factors like the weather and how much sleep you had the night before," says O'Brien.
As well as promoting good habits, your diary will spur you on - just try looking at an insulting entry such as 'couldn't be bothered' without grabbing your running shoes.
Not swotting up on a race
Every race is different, but your preparation for each should be precise and complete. Taking part in an event without knowing the intricacies of the course will cost you time before you have even climbed in to your wetsuit.
"I'm almost obsessive in my preparations, and it helps," says longtime triathlete Tim Rogers. "I find it useful to go to the course the night before and drive round it. I take my bike with me, stop to ride the corners and commit some of the landmarks to memory, so I know the sections of the course where I can carry lots of speed."
If a course is technical, you may require a different bike set-up, so always arrive early for a scout around or print out a map of the route the night before.
Not training in a wetsuit
You might not have to wear one if you are competing in sunnier climes, but if you are preparing for a UK event the chances are you will feel neoprene against your skin on race day - and it should not be a new sensation.
"You wouldn't use a mountain bike to train for a road race and the same rule applies to your triathlon preparations," says Dan Halksworth, a former Commonwealth Games swimmer who is now a triathlete. "I spent years training as a pool swimmer, so an essential part of my training is doing two sessions a week in the suit as it changes your buoyancy and technique."
Anything you can do to replicate race-day conditions is a must, so that means making room in your training plan for regular open-water sessions in a wetsuit.
Starting the swim too fast
It's natural to want to get off to a flying start, but exploding into the swim will eat into your energy stores.
Emma Smith, a European duathlon champion in the 25-29 age group, says, "Strong runners in particular often start the swim too quickly, but you need to be disciplined. Become too excited and it will come back to haunt you. Go at a steady pace and you will soon find yourself overtaking the people who rushed by you in a frenzy earlier on in the swim."
We all concentrate on untangling ourselves from the pack, but focus instead on finding a good starting position so the only thing you do at lightning pace is settle into your own race plan.
Not practising transitions
You've put in the hours in the pool, on the bike and on the pavements, but what about the so-called 'fourth discipline'. A fantastic swim can be quickly undone if you fumble around at the changeover.
"Transitions are hugely important," says Nick Morgan, Lead Sports Scientist at the Lucozade Sports Science Academy, "especially the bike to run. You have been working so hard on the bike but if you haven't factored transitions into your training, the first few minutes of the run will be a real struggle."
The only answer is to practise transitions and practise them again, particularly in the weeks leading up to a race, until you can make them smoothly and quickly. Develop a system that suits you and rehearse it until you can do both transitions in no more than 45 seconds.
"You should also practise things going wrong, such as your kit being moved," says Tim Rogers. "And use permanent landmarks to help you locate your bike."
Concentrating on your strengths, ignoring your weaknesses
It's been drilled into us since childhood - concentrate on what you are good at. Unfortunately, triathlon doesn't work like that.
"If you ignore your weaknesses, you can't compete," says Tim Rogers. "We all have a favourite discipline and you need to work hard to maintain your strength while also putting in the hours to improve your weaknesses. This will make a huge difference."
It's important to view the training sessions you usually dread as an opportunity, not a chore. "Write down your target time, memorise what your split times should be and isolate the areas where you can improve," says Rogers. "Then you can focus on learning the right technique and training to turn these weaknesses into strengths."
Not drinking enough on the bike section
With a steady headwind in your face or your mind fixed firmly on the road in front of you, it's easy to forget that you are rapidly losing fluid on the bike section. And the consequences can be disastrous, especially during the run, when carbohydrate depletion and fatigue start to set in.
"Cycling is the most important leg when it comes to hydration," says Nick Morgan. "You don't know how much fluid you've lost during the swim and you haven't yet been able to have a drink. But getting it right can lead to huge gains. To start with, make sure you take in enough fluids on the day and when you feel thirsty, drink. You can also set an alarm to remind you to drink at regular intervals and practise this in training until it becomes habitual."
Not writing a kit list
Forgetting an essential item on race day may not derail your event completely, but it could push your name further down the list of finishers - or at least lead to some serious chafing. If you don't want to see months of hard work undone by a moment's carelessness, keep a checklist of all the kit and accessories you need.
And not just for races - make it a part of your training routine, too. "I always keep a kitbag with me that contains everything I would need for a race," says Dan Halksworth. "Keep a checklist with it and go through it regularly, ticking everything off as you go along. That way you will stay organised and know if you need to buy or replace something."
Not concentrating when you're cycling
It is easy to mentally switch off once you have settled into your cycle, but this really is not the time to be distracted by pleasant scenery or a herd of dozy cows. If you fail to pay attention when you're training, you won't get the best out of your sessions, but if you tune out in a race situation you will lose ground to more focused competitors.
"Mental acuity is essential," says Tim Rogers, "and to make sure I don't lose concentration on the bike I am constantly measuring my current speed against my average speed. Always, always try to improve your average speed and fight, fight, fight until you get there."
Focusing on other competitors
You may be terrified by the sight of a 6ft 5in Michael Phelps lookalike warming up next to you in the starters' enclosure, but there is another person with even greater potential to crush you into a pulp: you.
The giant beside you is going to beat you anyway; whether you join him at the finish is up to you. "We're all competitive and if someone passes you, then you naturally want to pass them," says Emma Smith. "But remember that we're all different and that there is a chance they will blow up later on. It's a three-discipline sport, after all. And if they don't fade, then they're just a better athlete than you. So focus on your own race and just get on with it.