A contact delete limit is the number of contacts you can delete from your account in a month’s time. For all paid accounts, the delete limit is around your contact limit.
If you are on a monthly plan, the delete limit will reset around the first day of your monthly billing cycle.
If you are on a yearly plan, the delete limit will reset on the same day of the month as your annual billing cycle. For example, if your yearly billing cycle starts on March 15th, then your monthly delete limit will reset each month on the 15th.
You may run into your delete limit if you are deleting contacts one-by-one, or via engagement management tool, batch actions, or deleting contacts in bulk from the Contacts Overview page or Lists page.