A room is usually guaranteed until a certain time. After that time, you are considered a no-show and it may be rented to someone else. For this reason, most hotels have a check-in end time. Otherwise, it will state Your room is guaranteed for late arrival, usually in cases where they have already taken the payment, or at least enough for the first night.
You have not specified the end of check-in time, which sometimes is not even provided! It depends on the particular hotel but something between 10 PM and midnight is common. Any time you expect that your arrival will occur during or after those hours, simply call the hotel and let them know that you are coming and an approximate time. Do not forget to factor time to disembark, collect luggage, customs, immigration, waiting for transport and getting to there.
There is another case which is usually specified clearly and that is when check-in is impossible after a certain time. The only times I saw this was for a few small properties in Taiwan where the front desk is not open after certain hours since the attendant goes home. Early check-out also involved leaving the keys in an agreed-upon location.