This is the question that generates the most support messages in the first week of a subscription, and almost all of them come from the same misunderstanding.
Connections are not devices
A connection is one stream playing at a time. A device is a thing with a screen. They are unrelated numbers, and the subscription only limits the first one.
Install the player on your television, your partner’s phone, a tablet, a laptop and a spare Fire TV stick in the bedroom. All five hold the same credentials. With a one-connection plan, any one of them can play at any moment — and starting a stream on a second will typically interrupt the first.
So the real question is about simultaneity, not inventory.
A rough guide by household
One person living alone: one connection. You cannot watch two things at once. The only reason to go higher is if you habitually leave a channel running in one room while watching in another.
A couple: one or two. If you mostly watch together, one is genuinely enough and the second connection is money for nothing. If one of you watches sport while the other watches drama, buy two — the alternative is a negotiation every evening.
A family with children: three or more. Children in a separate room is the classic case. Count the rooms, not the people: two children watching the same thing in the same room is one connection.
A shared house: one per person who watches independently. Housemates do not coordinate viewing, so this is the one case where the device count and the connection count converge.
What running out actually looks like
It is rarely a clear error message. Depending on the player you may see a stream that will not start, a stream that starts and immediately stops, a spinning loader that never resolves, or — most confusingly — someone else’s programme being interrupted in another room.
That last one is worth knowing about, because it leads people to report a fault that does not exist. If interruptions correlate with someone else in the house starting to watch, you have found your answer and it is not a technical problem.
A sensible way to decide
Spend one week paying attention to how many screens are genuinely running at the same time in the evening. Most people guess high, because they think about the week’s peak rather than its average. Buying for the peak means paying for capacity that sits idle six nights out of seven.
The better approach is to buy for the normal evening and ask about adding a connection if the peak turns out to matter. Adding one mid-term is usually straightforward; a refund for capacity you never used is usually not.
Things that quietly consume a connection
A player left running on a television that was switched off at the wall may hold the stream open. A phone with the app in the background can keep playing audio. A second player app still signed in on an old device can do the same.
If your connection count looks right but you keep hitting the limit, do a sweep: close the app properly on devices you are not using rather than just turning off the screen.