One of the first books I ever loved follows the first-person perspective of a single character for about three years, and it’s so rich in detail that you live practically every day with the heroine. Except for that weird chapter that begins with a shocking sentence. In that sentence, the author skips ahead an entire year. Skipping time is an often-used fiction device, and it’s often jarring and upsetting. That’s probably because authors rarely do it really well.
In the book I’m making an example of, the narrator carefully details a year while living inside a very strange environment. The reader sees every detail, thought and spoken word unfold. I don’t think a single day is left out. Then all of a sudden, a year flies by. It’s just one sentence, and the first year took many chapters. No matter how you want to read it, that’s a jarring change of pace. It takes a few paragraphs to get back into the flow of things, after that. If your book is strong enough, you can always get over a rough spot.
...But why would you want to have a rough spot?
Some time skips are jarring; others are infuriating. I almost flew into a rage when I read chapter after chapter after chapter about an epic journey in a book I’d waited years to read. Hundreds of pages of walking from one place to the next, and at the end of that trip it was necessary to walk all the way back -- a feat accomplished with, I kid you not, one sentence.
Skipping time becomes necessary sometimes, but it goes much smoother with the reader if you find a way to write it that feels okay and doesn’t interrupt the rest of the story. Always skip time, if you can, at the beginning of a chapter so that it feels a little more natural. Ease readers into the skip, when possible, by still providing a description -- however brief -- of the missing time. Don’t do it abruptly, unless you’re planning to shock the readers.
Make your time skips as smooth as possible when you have to use them. Otherwise, you will literally be stopping and re-starting your book. Anything that takes readers out of the story, even briefly, is best avoided.