If you go with a descent ISP it should not be a problem. a good isp manages contention in a way that stops the user from even noticing that it is in play. e.g
ISP A (The good isp) has sold 1500Mbps total in subscriptions, but has only bought 250Mbps of capacity.
This means that at any given time their contention ratio is 1500:250 or 6:1, ISP A being a good ISP purchases extra capacity whenever their up link capacity is saturated for example if during peak time they discover that their customers are in fact consuming 300Mbps of bandwidth they will make sure to upgrade their up link capacity to suit the demand(new ratio of 1500:300 or 5:1).
IF ISP's follow this method of thinking contention wont really be a problem for the end user as even though the ISP does not have enough bandwidth to suit the needs of all their customers maxing out their lines at the same time, they have recorded past usage statistics and should have enough bandwidth to suit the actual usage at any given time based off past observations.
The problem comes in when ISP's do not upgrade their Up link capacity to suit the needs of their clients which then leads to slow downs and higher latency.
maybe
@PBCool could give some insight into contention as at the end of the day he/she sees the effects of contention in their workplace on a daily basis and would have a better understanding. and by the amazing results I have seen from CISP he knows allot about managing contention properly.
With wireless though another factor has to be taken into account, The towers capacity e.g if i put up an LTE tower, its capacity is based on the spectrum it has been assigned and the technology it is using (LTE, Ubiquity AirMax etc) and acts as another bottle neck for contention before uplink, Just unlike Uplink it is allot harder to upgrade capacity as a provider can not just magically allocate themselves more spectrum to make their services work faster (This phenomenon is known as Spectrum Crunch)
