I personally never found the need to change the gearing on my IGH. I've biked in the winter, in the summer, with nothing on the bike, and with the bike loaded up with gear for overnight camping 40 miles away. I always found the bottom gear was low enough, the top gear was high enough, and I generally stayed in gear 4 or 5 on the flat.

If you're worried about gearing, a regular derailler is a far more flexible choice. If you don't want to do maintenance, an igh with a belt completely eliminates the source of regular maintenance by getting rid of the chain.

(To be fair, I don't own a bike with a belt so there may be drawbacks I'm unaware of, I just own an IGH with a chain which was the only thing available at the time I needed a winter bike.)