The same happened to me recently. The tire was fine when last ridden but a week later did not have much air (i.e. it was flat but not squashed on the floor flat). I decided to pump it up and ride. I had no problem on the ride, but the next day it was flat again so I then opted for repair.

So yeah, you'll end up repairing it anyway so do it if you have the time. If you don't have the time right then, or are a bit bold, there really isn't much downside in the pump and ride strategy. Slow leaks are slow leaks and rarely get much worse. So the most you'd be up against is pumping up a few times on your ride.