Learn how to nail this one item consistently, and you will greatly increase your odds on advancing to finals. Neglect it, and you'll likely be playing one-and-done on audition day. We're talking about knowing the speed limits of each excerpt.
Before auditioning we need to be very familiar with tempos. Going too slow gets you stopped. Exceeding the limit also gets you pulled over. But worse yet, they catch you rushing, and you're eliminated and sent home on the spot. The good news is that you can work as hard as you want on this, and your chops will never get beat up. In fact, you don't even need your trumpet. Anyone can master it, and because it's an internal skill, nothing hurts! Let's fast forward to audition day and see how well you have prepared your tempos.
Picture yourself at the audition carnival, sitting on top of a trap door over a large tub of water with an L on it. You will be expected to play every excerpt at the right speed for the audition committee. They will be watching and listening intently as they seek to knock off each contestant with bad tempos. (You are still wondering why there is an L on the tub.)
Someone calls out "Bartok Concerto, second movement!" You must instantly play the right tempo or you get doused. But you're ready, and you nail that Allegretto scherzando perfectly! No stuffed panda prize for that dude! You're still there standing, or sitting proud.
Next, "Outdoor Overture!" Even though it calls for a speed limit of 76, for some unknown reason you panic and play too fast, and then rush badly all the way down the two octave scale. Click, and you hear the music to "splish, splash, I was takin' a bath!" You hear the laughter as the audition committee is having themselves a good old time.
The audition monitor hands you a towel and props you up again for another chance. Next, a jury member barks "Schumann 2". Being under-prepared, you panic. Paying little attention to intonation or rhythm, your bad tempo selection quickly triggers the release button. Once again you are listening to your unfavorite tune of the day while plunging headlong into that large tub with the L on it.
Now that's two strikes against you. Maybe you can redeem yourself with the next one. "Heldenleben, the E flat solo!" Your heart begins to simulate the percussion intro, and you can't feel your legs or much of your upper lip. Nevertheless, you stab in the dark valiantly with atrocious accuracy and horrible intonation. Nerves and stiff chops seems to have short-circuited your thinking as your tempo is way too fast. The famed battle scene is not happening, and instead of deftly wielding your weapons, you are taking a lot of hits. (They should have heard me yesterday!) Click, you hear the music again, and that once proud sitting duck now feels like a dead one.
"Alright, thank you. Next candidate!" Now you know what the L is for as you slink to the stage door slipping and sliding away.
Of all the things that might go wrong, your tempo selection should never be one of them. Start with a good steady correct tempo which will be the rock solid skeleton on which you build everything else. Don't be a sitting duck for the tempo police.