Spot checks

[Tobold Hornblower]

But there's a problem here. The rules are set up so that you can never, never, see someone (or a group of someones, such as an army) greater than 720 feet away, ever. But long range spells get up to 1200 feet at 20th level. What's the point?

Bows can get up to 1,650 feet. That's 930 wasted feet of range.

Remember, a moving army would kick up a lot of dust. Spotting that dust cloud is easier than spotting the army--probably automatic at distances well beyond 1200 feet.