A motorcycle GPS costs the same as a high end phone (roughly 600 bucks), so the cost of replacing a GPS is comparable with a phone. There are cheaper GPS units available, and there are cheaper phones as well. For redundancy, I carry my old phone. I use a mount which has a chance of leaking water into it, worst case, if the phone goes bust, I swap out the older phone. It's the same micro usb charger, and fits in the same cradle and is less bulkier to pack than a GPS. That way, I have redundancy for my phone, music and GPS. It's somewhat important for longer trips where I need a spare, for shorter ones, I wouldn't bother at all. I've also had my phone really wet a couple of times and it's held up very well. It is not IPX7 or anything, but from a layman point it works out well for me.