To counter the top 5-10 thing, with all due respect. It's something I've been told over and over, it's something that was pounded into my head when I started racing, and it was something we all strived to do back in the day.
What I realized pretty quickly is that, first, it took an immense amount of power (later I could define this as FTP) to stay in the top 5 or 10. You're constantly responding to moves, you can't relax, it's very difficult. This for anything where the field isn't organized, like UHC dragging the field around for 20 or 30 laps with rider order basically unchanged the whole time. In my life I've only experienced that kind of tactical nothingness once, and it was when two guys pulled the rest of the field around for about 13 or 14 minutes. We literally didn't change order behind them for that time. It was as if someone hit the "pause" button. Literally nothing happened to develop the race, even in the field.
So for normal riders (the ones writing the books seem to be pretty good, like ex-pros and such), holding a top position in a field is very, very difficult. It may not be difficult to get there, or to be there for a minute or two, but to do it for the duration of the race? Frankly it's very wasteful. If a rider is skilled enough to sit top 5 or 10 in a race then they're skilled enough to also sit 25th or 30th and save a ton more energy, all while being in virtually the same tactical situation.
When I sit at the back a lot of the potential race winners, riders with literally dozens of national titles (one has something like 30? titles, others have "only" 5 or 8 or something), are sitting there with me. They move up earlier than me because they can. I have to wait because moving up at 5 to go means I'll be blown up before the bell. If I'm super aggressive I move up at 5 to go, 3 to go is if I'm feeling really good, and 2 to go is if I'm feeling normal. 1 to go for certain courses and also if I'm hanging on for dear life anyway.
Although I'd be a bit horrified if someone actually tried to copy my own tactics (because I'm assuming that everyone is physically more capable than me so no one should sit at the back as late as I do) I've waited until the last lap to move up from literally the back of the field. I caught it once on video, but before the camera it was almost an inside joke. I'd be 10 or 15 feet off the back of the field at the bell, turn to a buddy (for some reason the same guy used to be around, usually because he would do my race for training after "racing for real" in an earlier race, and he usually sat up at the bell), and say, "Okay, it's miracle time." Then I'd move up, hope there wasn't an effective (not just organized, effective) leadout, and try to place. I've won races like that and placed 2nd and 3rd a number of times. The shelter in the field can be so significant that such moves can be possible, if you have enough leg speed (for moving up) as well as a decent sprint.
Here I move up with less than half a lap to go, lead out the sprint, and get passed by two guys. One of them is a multi time Masters National Champ, he pips me at the line, and really, I was so wasted that I'm surprised more people didn't pass me. In that race there was a leadout, but it was ineffective. Tactics were there, execution lacked.
In another race I was pretty well buried coming up to the finish (at about 7:20). A friend who raced on the blue team (working against me) said that he even told his teammates on the backstretch, yeah, "He (meaning me) is stuck back there, we're good for the sprint." He was one of the last riders to leadout his teammate Bryan and he said he almost fell off the bike when I went blowing by him. Both him and Bryan joined my team shortly after.
So one aspect of it is that I moved up pretty hard even when the group was going pretty fast (they were going 33 mph?). I was doing about 35-36 mph, I must not have broken 36 mph consistently else I'd have put "36+ mph" and not "35+ mph" in the clip. People talk about how you don't need a 53 or an 11 (or, what I used to use for about 10 years, a 54T, and, for a year recently , a 55T because that's all I had). The thing is that with a big gear I can move up without spinning too much (spinning really fast will accelerate your heartrate). I can do more of a leisurely move up rolling a 53x11, while other guys may be spinning a 12 or, worse, a 50x12, etc. I recommend all racers, even for flat races (especially for?) to have big gears. With airfield and other flat races you could have a 20 or 30 mph tailwind and you might be holding 42-44 mph on that straight. Doing that in a 53x11 is much easier than a 53x12.
In the clip below there's a descent at the beginning, maybe 2:15 in. I don't think we went much more than 45 mph so it wasn't super fast. You can see some riders trying to pedal really fast, meaning they were in a bad gear or they had too low of a high gear. Much more stable soft pedaling or doing a tuck. Guys in white (a group based on their matching kits) pass me, they seem pretty fluent, and there's a "Quick Step" guy in there. The QS rider keeps going, I follow. QS rider has an 11, I only had a 12. You can see how he's pedaling within reason, no crazy spinning. I couldn't do much until the road flattened out. Then I got shelled, of course. (I only had about 50-60 psi of air in the tires because I was late to the ride, no gloves, etc, so normally I'm gloved and I can corner better).