At the moment I have a HG 11-36 11-speed SRAM cassette on my bike with a 46/30T crank, and I am not ashamed to use the lowest gear on >15%.
My rear derailleur is a Shimano Ultegra Di2 officially rated for 11-32T. The b-screw is your friend.
Off-road, where I can't stand up without spinning out, it is essential.