What should I avoid before a tri?

Surprises--which means knowing yourself and your gear. As important as eating, sleeping, and training correctly is knowing your equipment. This means using the same shoes, bike settings, and swimwear as you approach your big event. You wouldn't wear running shoes for the first time on race day--the same is true for wetsuits. A good guideline is to avoid gear or dietary changes in the two weeks leading up to your race.