As my family will tell you I have lots of books. There are bookcases in my study (2), in the lounge, in the front hall and in the dining room (2) to say nothing of the many boxes of books that live in the utility room or in the walk-in wardrobe upstairs.
Once a book has been relegated to the boxes in the utility room they have little chance of every being read again. To slightly paraphrase my daughter, "I will store them there until I die, then somebody else will throw them away." Some of the boxes I looked at today had been sealed up for nearly 20 years which both amused and shocked me.
After many years of "living" in the dining room my set of Jennings books have been packed up and will probably not emerge into the daylight again in the foreseeable future. There are 23 novels in the series and it is a curious fact that although I have read some of the books many times there is one I have never seen, never mind read. Jennings at Large (#23) was an experiment by the author that didn't work according to many other enthusiasts and so I have never felt motivated to search for a copy.
The Jennings books are timeless in that the hero stays the same age throughout the series. This of course is a strength and a weakness but by the end of the 23 books all the best story lines have been used over and over again. Other series gradually allow the characters to age (The Lone Pine series does this) and the famous Chalet stories are spread out over many years and perhaps they benefit from this editorial decision.