Estimated lifetime: For LED light you will often see ridiculous
amount like 50,000 hours or so, but in reality those are not marketing gimmick.
What manufacturers do is push more than normal current to produce a certain
output power which reduces the lamp life significantly.
I will be blatantly honest here, this book is Rubbish. First of all let us look at the format, it comprises short stories written by many authors, editor here did nothing, he just copied and pasted the whole thing, didn't even care that the same information is there like 5/6 times.
For example let's look at the story of "1200 Kanchonis and their 80k cost" it came in page numbers 37, 85, 104, 117, 129 and 132. That much repetition in a single book shouldn't be allowed and it is not the only occurrence either.
The story about "Bibekanondo addressing a dancer as Mother" was in page 76, 79, 91 and 135. I mean what was the editor doing? Just increasing page count so that he can make some money? Is that all there to it?
Not to mention the amount of spelling mistakes in there, it is staggering
Overall not a book anyone should buy, any other old stories about Dhaka city would have been a better book than this one to get the same information.