Battery range for long commutes

Hey everyone!

I'm new to the forum and stoked to be here. I've been eyeing an e-bike for my daily commute, which is about 20 miles each way, with some decent hills involved. My main concern is battery range – I really don't want to run out of juice halfway home! For those of you doing longer commutes, what kind of battery capacity (Wh) do you find is truly reliable for a round trip without needing a charge at work, especially with some assist? Any tips on managing range with hilly terrain would be awesome too!