Coterminous means ending on the same date. A coterminous order is one whose term is set to finish on the same day as an agreement you already have with that carrier, instead of starting a fresh 36 months on the day it is installed.
Most companies add telecom services a few at a time over many years. Each new order starts its own term, so after a while a single carrier account has a dozen end dates, each renewal is negotiated on its own, and there is never a moment when you could move the whole account somewhere else. That is not an accident. It is the default, and it works for the carrier.
Why staggered terms favor the carrier
Each renewal is small, so nobody shops it. The carrier knows you cannot move the account because something is always mid-term, and the early termination fees on the services that remain make switching look impossible. The result is that the price of the account as a whole never gets a real test, and the renewal offer on each piece is priced accordingly.
Lined up on one date, the same services become one negotiation with a real alternative behind it. Carriers price that conversation differently.
Ask for a coterminous term on every add
When you add a site, a circuit or more seats under an existing agreement, ask for the new order to be coterminous with the master agreement. Most carriers will agree. The usual conditions are a minimum remaining term, often twelve months, or a slightly higher monthly rate on the short piece. Both are normally worth it.
Write the words into the order form, for example "Term: coterminous with the master agreement dated March 3, 2025", and check that the signed order carries them. An email from the account manager is not the contract.
When you do not want it
A service with heavy construction or install charges may need a full term to spread those costs, and the carrier may not offer coterminous pricing at all. A service you expect to drop before the master term ends should carry its own shorter term. And if the master agreement renews soon, a new service added coterminously will be swept into that renewal, which is fine only if you have already decided to stay. In those cases ask for a shorter term, or for the right to cancel that one service at the master end date without a fee.
Lining up what you already have
You cannot change a term that is already running, but you can choose the length of every renewal. Pick one anchor date for the carrier, usually the end of the largest agreement, and renew each service for the number of months that lands on it: twenty months instead of thirty-six, for example. Carriers allow odd-length terms more often than people expect, especially when the alternative is a non-renewal.
Within two or three years most of the account shares one or two dates. Put the anchor date on the calendar with notice reminders at 120, 60 and 30 days, and the next renewal is the whole account at once, with quotes in hand.
DemarcLabs lists every contract by its end date and notice deadline in one grid, so it is easy to see which services already share a date and which renewal to shorten next.