Not As Much As You Might Think:
Time gives chance opportunity to do its evolutionary thing. But lots of factors can affect this as well. Your planet might be filled with frighteningly efficient competitive organisms - or be not be all that much more sophisticated in biology than Earth. Or it could be long dead.
First, your radiation is lower. This slows down random mutation. Lower mutation means slower change. Stable geology similarly reduces harmful, irregular mutagens oozing out of the mantle or bubbling up from deposits deep underground. All that slows evolution.
Second, disasters stir up opportunities for change and new organisms. If not for the K-T Dino killer, large dinosaurs might still rule. If not for the even bigger (likely volcanic) Permian extinction, dinosaurs might never have had a chance to compete with the dominant animals that came before. So without apocalypse to stir the pot, evolution may stall out on your world. It sounds like even the weather might be stable and temperatures could shift slowly, giving even poorly adapted creatures time to adapt and maintain their status in the ecology.
But there may also be limits to the life of your planet. As the core of the world cools and the planet isn't protected from radiation by a magnetic field, the atmosphere and seas may slowly be ablated off the planet. The slow shift of the output of the star might move the world out of the habitable zone and it could just freeze or cook. A nearby supernova might simply kill everything. The odds of a supernova probably go up with time. An intelligent creature from another world might come by and casually destroy the local life for stuff more like them.
There is one upside to evolution here, and that is the possibility that bigger metabolic adaptations in highly conserved functions would have time to occur. The rise of free oxygen production was one such event that transformed Earth, and the evolution of fungi that could consume wood sort-of ended the carboniferous period. Metabolic changes we haven't even considered for life might evolve here that take advantage of processes we haven't considered for life. This COULD mean that everything gets more efficient, OR that a super-bacteria kills and consumes all life like a "grey ooze" scenario.
Of course, all this is speculation. We really don't know what would happen for sure. Find one of these, and get back to me in 20 billion years.