My first tour of six months I never had one, I just used a solar panel. At that time I only had a smartphone that needed charging, so I got by... but sometimes it was cloudy for a week, and I was forced to find an outlet. I decided on that tour that I wanted a dynohub. It is much more convenient than having to position a solar panel on your rack. On my next tour of four months I had a dynohub and a solar panel. I also had more things to charge; Garmin gps, smartphone, digital camera, lights, and battery pack. Never ran out of juice, ever. The dynohub needs to be spinning atleast 15km/h to make a charge, so when I was in the mountains the solar panel came in handy, or if you want to camp out for a couple days. If you have the money, go for it.