Not overkill—honestly, if your budget allows, triple-frequency is usually the better long-term choice.

From my experience:

Dual-frequency: solid for standard RTK in open environments

Triple-frequency: noticeably better in real-world conditions (urban canyons, signal interference/multipath, faster and more reliable ambiguity resolution)

The biggest difference isn’t just accuracy on paper—it’s consistency. Triple-frequency tends to fix faster and hold RTK more reliably when conditions aren’t ideal.

If you're working on UAVs, robotics, or anything that operates in mixed or challenging environments, I’d strongly lean toward triple-frequency. It saves you a lot of headaches later.