Here in Sweden the life of a running shoe is said to be 1000 km, which is about 620 miles. So it obviously differs depending on where you are and it is therefore important to remember that these distances are recommendations and not rules.
I agree with what has been written above, have several shoes in your rotation as that makes it easier to feel when a pair is on it´s way out.
That´s it. My result was 3:36:27 so I managed to do a new personal best (old one 3:38). Felt like I had pretty much power left at the end of the race and as it was blazing sun and headwinds periodically I think it is possible for me to run even faster. But I´ll do that the next time. Otherwise, I think it was a nice race. A lot of spectators and good support along most of the track But km 22-27, from where the half-marathon runners turned off to finish until we were inside the Prater again, was a bit boring. The City of Vienna was also nice alhough it was a bit annoying with the classical music that was played exactly etverywhere. The match between Rapid and Salzburg on Sunday evening was also good and dramatic, when Rapid went up from 0-3 and equalized 3-3 in overtime.
I don´t understand German but according to Google Translate this is what it say:
"Clouds and sunny all day phases alternate from each other, to go, especially in the morning and then again in the afternoon rain showers down. Thus, the weather is often dry during the marathon. The wind is weak to moderate from west to north with peaks between 20 and 35 km/h. Are at the start of the marathon, the temperatures around 13 or 14 degrees at noon to 18 or 19 degrees. We wish all participants every success in this year's marathon"
It doesn´t sound that bad, even if I would have prefered a few degrees colder and no wind.
This video from last years race was put up on a Swedish running forum and it gives you a feeling of the race and course, including stomach issues (ugh!): https://vimeo.com/97869165
Most forecast seems to predict something like 20-21 degrees. However, they say it will be partly cloudy and as the hottest time of the day is usually between 2-4 in the afternoon most of us are likely finished by then.