i watch on the first episode and usually thats it. not to mention if i binge watch a season it makes the transition between episodes better without them
The openings makes me feel more connected to the series, so I never try to skip them. I rarely watch the endings however... unless they play it near the end of the episode (which I love). I almost never "like" an opening the first few times but that changes a lot after enough episodes.
If they're really good I'd barely skip xD. Experienced this with the Erased, Samurai Champloo and Noragami s2 openings. Only ending I never skipped was Tokyo Ghoul.
When the opening/ending is new, I watch it. If I like it, I don't skip it for the next 2-3 episodes, but after that I skip it too. If I do not like it at all, I skip it always.