Commuting distance recommendations

Hey everyone!

I'm curious to hear about your eBike commuting experiences, especially regarding distance. I've been eyeing an e-MTB for my 15-mile (one way) commute, which has a few decent hills. For those of you who commute regularly, what distance do you find is the sweet spot before it starts feeling like a chore, even with pedal assist? Are there any specific factors that make longer commutes more manageable for you?