It just rains any time and I fear my phone will get wet. So I started carrying my phone in a plastic bag. This was pretty common thing to do, but not for me because I never knew about it. Thought there might be many others like me and they ought to know:)
If you are looking for travel directions you can just take a screenshot of the Google Maps instead of keep using the internet and wasting battery. Another trick is to take a photo of your car parking area so you know exactly where your car is parked during rush hours.