This is a very tricky question to answer because it would depend on what your definition of a plot hole is. The traditional belief is that a plot hole is something in the story that either allows for illogical things to occur or where things happen that contradicts what has already happened before. The problem with a lot of books is that authors try to be too clever and end up writing themselves into a corner. The only way out of it is to then come up with something far-fetched and illogical to resolve their conundrum. This is very disappointing for readers as they read in suspense, expecting to find out how the impossible is going to happen, only to find out that the author didn't know either and just faked it. You can think of it as the literary equivalent of those television shows that end in a cliffhanger of the hero being in a building that explodes, only to walk out at the start of the next episode looking only a little dirty. It insults the intelligence of readers and has spoiled many a good book as well. If only some authors would put a little more thought into their overall stories this wouldn't happen so much, but the problem is that a lot of authors write books in a series these days instead of stand-alone novels, which makes it way harder to keep track of all the loose threads. A good example of the latter would be A Song of Ice and Fire. Now before anyone starts attacking me, I love the books to death, but anyone who has read them will know that they are full of glaring inconsistencies. I'm not going to go into any specifics for the sake of those who have not yet read the books or watched the show, but suffice to say that they are there for all to see. The Harry Potter series is another good example, although it is quite amusing to see some of the fan theories that have popped up over the years to try and justify them!

Other readers may have more detailed and specific answers, but for me I've personally kind of given up on reading any books about time travel because of the plot holes. I really can't think of any book that features any type of time traveling that doesn't rely on all kinds of convoluted explanations to get away with them. Even some of the most popular books of our time, like the Harry Potter series, tried to include a time travel gimmick and honestly just ended up being worse for it.

Oh and another "plot device" that really ruins books for me is when characters impersonate other characters and somehow get away with it without anyone noticing that they are imposters. This is probably also the reason why I was never a fan of the Mission Impossible movies, but there really is no excuse for authors to resort to this type of lazy gimmick to cover plot holes.

Plot holes are something every author who writes books that are part of a series instead of stand-alone novels have to deal with. It's easy to think that it is something that only novice writers encounter, but there are a surprising number of "big name" authors who are guilty of plot holes too. Even the mighty J. R. R. Tolkien wasn't exempt from it either when he wrote his Lord of the Rings titles and George R. R. Martin has fallen prey to them as well. I have encountered the most amount of plot holes in fantasy books, but thrillers appear to be quite susceptible to them as well. My favorite example is Dan Brown who is a world famous author, but scrutinizing any of his novels too closely reveals a staggering amount of plot holes. What makes it even more amusing is how he claims that everything is based on real facts. The amount of characters in books who are severely lacking in common sense purely to drive the plot forward is also a topic that could cover volumes.

If the purpose of this question is to try and avoid books with plot holes then I have some bad news for you, virtually every author and book under the sun has had the fudge things at some point for the books to make sense. I have a few author friends and they have all told me that the average reader is usually so engaged in a story that they don't notice when a character manages to be on three different continents in the space of one day to accomplish something or whether the actual cost of jet setting off to all the exotic locations in the book would bankrupt the average person, not to mention put a serious dent in their time off from work. If you are a huge author with a whole team of people who can hunt down all the continuity errors and plot holes for you, then great, but for the average author it is just not feasible to obsess over every little thing just to make sure that some compulsive reader can't find fault when going over your work with a fine tooth-comb.

Something that a lot of people here are missing is the fact that factual errors are not plot holes and neither are inconsistencies. Books require us to suspend our disbelief, so that we can be entertained. I don't care if the author spent five months living in a nuclear fallout shelter just so he can write an "authentic" post apocalyptic novel. I also don't care if that nuclear bomb he writes about operates on magical dust and super smart hamsters. What I care about is whether or not the plot is interesting, the characters engaging and the world compelling. The rest is all just gravy in my opinion.