Running a marathon requires constant monitoring of various parameters:

• How do I feel overall?
• Is it too hot or too cold?
• Can my legs hold up?
• Am I eating enough, but not too much?
• How is my stomach doing?
• How hydrated am I? Am I losing more or less fluids than expected, which requires adjustments?
• Am I maintaining the planned pace? Can I push a little harder or should I slow down?

  The list is long.

So, yes, it makes sense to have a general idea of what a realistic achievable pace is on day X. But there are many more things to consider when running a marathon than just speed. Here are some valuable tips, gathered from a great deal of experience:

1. Pacing the first 10 km: This is the point where many runners struggle. The excitement is high at the beginning, you feel fresh and your adrenaline is pumping. It’s easy to start at an unsustainable pace and realize your mistake when it’s too late. There are two possible solutions: if, for example, your goal is 3:30 and there are pacers for that time (the ones with flags on their backs), stick to them at least until the middle of the distance, no matter how good you feel. If there are no pacers, follow the pace of your watch and stick to it for the first half. After 25 km, evaluate how you’re doing and if you still feel good, consider whether you can (and want to) increase your pace slightly.
2. Food: neglecting nutrition will lead to so-called bonking/hitting the wall. Hoping that things will magically fix themselves, or planning to „make it up“ during the race, can lead to a tough last 10 km. We can only store a limited amount of carbohydrates, no matter how much we „load“ before the race. So don’t neglect nutrition. Generally speaking, aim to consume at least 50g of carbohydrates per hour (usually this equates to 2 gels from most manufacturers every hour).
3. No experiments on race day: This is a mistake that (too) many athletes make. The day before a race, a friend shares their favorite new gel or the latest speed running shoes and you decide to try them out too. What could possibly go wrong? Well, a lot. They've tested them in training and tailored these elements to suit their needs. There's nothing wrong with trying new things, but definitely not on race day (trust me).
4. Knowing the route: Familiarize yourself with the race course. Where are the food/water stations located? What is available at each station? Is the course hilly or flat? Are there any specific turns or sections to watch out for? What is the expected temperature on race day (hot, cold, humid)? Is it allowed to receive food from spectators/friends? The more you know about what to expect on race day, the better prepared you will be. Make as many of your decisions as possible before the race. The likelihood of making a better decision after the 30th kilometer than before the start is minimal.
5. Other variables: Even if you're well-prepared and your training has gone according to plan (which is rare), consider external factors. Last-minute illness, travel stress, etc. can all affect your performance on race day. Unless you're an elite runner where every second counts, it's usually wise to start a little slower than planned and increase your pace after the first hour if you're feeling particularly good.