I haven't run as many cable as some of you, but probably more than the average person thinks is reasonable.
Generally I have one bedroom with only one Cat6 socket, but the others have two, three, and four respectively. I have 2 cat6 to the front door, along with a power cable and a KNX cable. I have 2 cat6 to my boiler cupboard (one for the webserver for the heating system, plus an additional one just in case). I have none to the lounge (but all appliances connected directly to the electrical cabinet), one to the kitchen and two to the dining room. In addition every door contact and pir is connected by cat6, as is every in ceiling speaker and fire alarm sensor or sounder. I also have a one wire circuit in cat6, along with a number of spares to the roof space (about five left spare).
There's over a kilometre of cat6 in my house, the conduits in the wall are packed full, and I've almost run out of potential cable runs that meet building regulations.
Wish I'd run a few more outside to be honest, although I may be able to service those needs from the spares in the roof space.
You could argue for more, but I've got enough. There comes a point where there is a practical limit. The cost of running the cable and terminating all the connections was not insubstantial. Simply because there were a lot of them.
Remember to buy yourself a good label printer, label every cable at both ends as you lay it. Don't miss one. It will pay off in the long run. We only have one cable that is not working (to the power socked in the walk in wardrobe), and one not used (was for an extra dining room light but we've decided to make do with the two). Considering how many cables that's not bad.
All of the cat6 has tested out ok.