My 1030 backlight works great. At sunset, it switches to a dark background with white letters to preserve night vision. The backlight is on all day, to help see it with my dark sunglasses. I think it lasts at least 12-16 hours, but I've never tracked the total time between recharges. (The smaller 830 has similar features, but the battery life is much less, more suited for 8 hour or less rides.)

For loaded courses:
I often keep the Elevation screen on the display, showing the next few mile's elevation as a graph. Very helpful for pacing.

On any screen display, as I approach a turn, it chirps, and the zoomed in turn map pops up, with a 30 second time countdown and a distance to turn countdown, and a white arrow pointing through the turn and the map showing. Nice! On the main navigation map screen, it shows the distance and road name of the next turn, even miles away.

1030 Plus
I see that the 1030 Plus replaces my 1030. DC Rainmaker review. He says 24 hours in "high navigation mode", 48 hours in a basic mode (likely with screen timeouts)

For even longer events:
There's a screen timeout option, and it turns back on when a turn is coming up (or when the screen is tapped?) I never use this, I check data screen or map quite often, and want to just glance down as needed. The timeout should extend the battery life quite a bit, I think.
It's possible to power the 1030 from a USB battery plugged in, but that would be annoying to cable up, and not waterproof.

The included out front mount has a pass through for a companion battery that mounts on the bottom side and connects to contacts on the Garmin. An extra 24 hours! Garmin Charge Power Pack. pricey.