alba - // would anyone like to know how many spiders the average human, in the average life-time eats whilst they're sleeping? //
That would actually be none!
https://www.snopes.com/fact-check/swallow-spiders
It's a myth as old as the internet itself, and was actually placed there in the very earliest days of the Web to see how fast it would circulate - the answer is, very! And it still does today.
As the explanation points out, spiders are far too fastidious to venture near a human mouth which is expelling moist air and noise - they would simply walk the other way.
Similarly, my grandmother always kept the plugs in her sink basin and bath because she believed that spiders crawled up the waste pipe to get into them.
I pointed out that there is the small matter of the u-bend which is full of water, which would prove a lethal obstacle, apart from the obvious fact that spiders are not keen on getting into damp pipes that gush water at regular intervals.
I also advised that the spiders she finds are simply travelling round the house and have slid into the bath sink or basin by accident, and can't climb out which is why she finds them there.
She never did believe me, bless her.