I never sped things up when watching or rewatching (unless it's an educational tutorial vid). Probably do OP/ED skips often but never increasing the pace in real time. It just spoils the viewing experience and even the dull pacing of a show is part of the viewing experience. I think speed running the episode is like speed running some good games you could have enjoyed the tiny details but overlooked it and then regretting later wishing you can play it again for the first time for those novel easter egg experience especially when there is a lot of action involved.