Or just carefully use levers 8-). Most of the above is unavailable "in the field" which is the only place one might be caught without levers. All of the above are handy, though, even with levers, for very obstinate tire/rim combos.

I can usually/often mount even tight tires without levers and always work the tire until I decide either that I can't or that it's not worth the bother. However, lately I've found that levers can also help prevent damage to the tube. Sometimes it's really tough to keep the tube inside the tire where it won't get pinched when you're mounting it. I find that you can poke the tube into the "safe zone" while gently levering the tire over the rim. This is especially true on difficult mounts, where I probably could do it by hand if I really tried hard, but why bother when the lever is easy and it protects the tube.