It is a growing problem. A few years back and most households only had a few computers. But the number of connected devices has increased dramatically since then and a household with 14 of them is by no means unusual. Unfortunately, the routers may not have kept pace. At home, most people use the router that their internet service provider supplies and this is often a case of you get what you pay for. Such 'free' routers tend to cheaply made, often only costing a few pounds to manufacture, with anaemic processors and small amounts of memory. They can service a few computers without any problem but start to falter in a larger household.
The solution is to buy a router with higher capacity, of the category sometimes referred to as 'prosumer' (i.e. professional consumer). These are routers that are typically priced around £150 upwards in the UK. An example of one would be something like the Apple AirPort, which is rated by the manufacturer as good for 50 simultaneous connections. Higher specification routers are also available from Asus, Billion and other manufacturers. Be sure to buy the right type; if you have cable or fibre then you need a cable router. If you have regular broadband over a telephone line then you want an ADSL modem router.