You get 60 days with the much more expensive Vertix 2 and that also has an always on display https://www.coros.com/vertix2
I have the Coros Pace, so can vouch for their battery life claims. I get between one and two weeks between charges, depending how much I use the GPS.
Didn't know about Vertix either. Great!
The garmin instinct 2 solar has the same screen tech as the pebble or an old nokia and NEVER needs to be charged.
Wow, that's probably the first time an always-on electronic device actually surpassed my Nokia 6310's 21-day battery life in the last two decades. It's really hard to imagine a cellphone charge lasting for three weeks today. How far we've come :P